Three days later, Strike and Robin received an unprecedented invitation. As a courtesy for having chosen to aid rather than upstage the police in passing on information about Flick’s stolen note and “Mare Mourning,” the Met welcomed the detective partners into the heart of the investigation at New Scotland Yard. Used to being treated by the police as either inconveniences or showboaters, Strike and Robin were surprised but grateful for this unforeseen thawing of relations.

On arrival, the tall blonde Scot who was heading the team ducked out of an interrogation room for a minute to shake hands. Strike and Robin knew that the police had brought two suspects in for questioning, although nobody had yet been charged.

“We spent the morning on hysterics and flat denial,” DCI Judy McMurran told them, “but I think we’ll have cracked her by the end of the day.”

“Any chance we could give them a little look, Judy?” asked her subordinate, DI George Layborn, who had met Strike and Robin at the door and brought them upstairs. He was a pudgy man who reminded Robin of the traffic policeman who had thought he was such a card, back on the hard shoulder where she’d had her panic attack.

“Go on, then,” said DCI McMurran, with a smile.

Layborn led Strike and Robin around a corner and through the first door on their right into a dark and cramped area, of which half one wall was a two-way mirror into an interrogation room.

Robin, who had only ever seen such spaces in films and on TV, was mesmerized. Kinvara Chiswell was sitting on one side of a desk, beside a thin-lipped solicitor in a pinstriped suit. White-faced, devoid of makeup, wearing a pale gray silk blouse so creased she might have slept in it, Kinvara was weeping into a tissue. Opposite her sat another detective inspector in a far cheaper suit than the solicitor’s. His expression was impassive.

As they watched, DCI McMurran re-entered the room and took the vacant chair beside her colleague. After what felt like a very long time, but was probably only a minute, DCI McMurran spoke.

“Still nothing to say about your night at the hotel, Mrs. Chiswell?”

“This is like a nightmare,” whispered Kinvara. “I can’t believe this is happening. I can’t believe I’m here.”

Her eyes were pink, swollen and apparently lashless now that she had wept her mascara away.

“Jasper killed himself,” she said tremulously. “He was depressed! Everyone will tell you so! The blackmail was eating away at him… have you talked to the Foreign Office yet? Even the idea that there might be photographs of that boy who was hanged—can’t you see how scared Jasper was? If that had come out—”

Her voice cracked.

“Where’s your evidence against me?” she demanded. “Where is it? Where?”

Her solicitor gave a dry little cough.

“To return,” said DCI McMurran, “to the subject of the hotel. Why do you think your husband called them, trying to ascertain—”

“It isn’t a crime to go to a hotel!” said Kinvara hysterically, and she turned to her solicitor, “This is ridiculous, Charles, how can they make a case against me because I went to a—”

“Mrs. Chiswell will answer any questions you’ve got about her birthday,” the solicitor told DCI McMurran, with what Robin thought was remarkable optimism, “but equally—”

The door of the observation room opened and hit Strike.

“No problem, we’ll shift,” Layborn told his colleague. “Come on, gang, we’ll go to the incident room. Got plenty more to show you.”

As they turned a second corner, they saw Eric Wardle walking towards them.

“Never thought I’d see the day,” he said, grinning as he shook Strike’s hand. “Actually invited in by the Met.”

“You staying, Wardle?” asked Layborn, who seemed faintly resentful at the prospect of another policeman sharing the guests he was keen to impress.

“Might as well,” said Wardle. “Find out what I’ve been assisting in, all these weeks.”

“Must’ve taken its toll,” said Strike, as they followed Layborn into the incident room, “passing on all that evidence we found.”

Wardle sniggered.

Used as she was to the cramped and slightly dilapidated offices in Denmark Street, Robin was fascinated to see the space that Scotland Yard devoted to the investigation into a high profile and suspicious death. A whiteboard on the wall carried a timeline for the killing. The adjacent wall bore a collage of photographs of the death scene and the corpse, the latter showing Chiswell freed from his plastic wrapping, so that his congested face appeared in awful close-up, with a livid scratch down one cheek, the cloudy eyes half open, the skin a dark, mottled purple.

Spotting her interest, Layborn showed her the toxicology reports and phone records that the police had used to build their case, then unlocked the large cupboard where physical evidence was bagged and tagged, including the cracked tube of lachesis pills, a grubby orange juice carton and Kinvara’s farewell letter to her husband. Seeing the note that Flick had stolen, and a printout of the photograph of “Mare Mourning” lying on a spare bed, both of which Robin knew had now become central to the police case, she experienced a rush of pride.

“Right then,” said DI Layborn, closing the cupboard and walking over to a computer monitor. “Time to see the little lady in action.”

He inserted a video disk in the nearest machine, beckoning Strike, Robin and Wardle closer.

The crowded forecourt of Paddington station was revealed, jerky black and white figures moving everywhere. The time and date showed in the upper left corner.

“There she is,” said Layborn, hitting “pause” and pointing a stubby figure at a woman. “See her?”

Even though blurred, the figure was recognizable as Kinvara. A bearded man had been caught in the frame, staring, probably because her coat hung open, revealing the clinging black dress she had worn to the Paralympian reception. Layborn pressed “play” again.

“Watch her, watch her—gives to the homeless—”

Kinvara had donated to a swaddled man holding a cup in a doorway.

“—watch her,” Layborn said unnecessarily, “straight up to the railway worker—pointless question—shows him her ticket… watch her, now… off to the platform, stops and asks another bloke a question, making sure she’s remembered every bloody step of the way, even if she’s not caught on camera… aaaand… onto the train.”

The picture twitched and changed. A train was pulling into the station at Swindon. Kinvara got off, talking to another woman.

“See?” said Layborn. “Still making damn sure people remember her, just in case. And—”

The picture changed again, to that of the car park at Swindon station.

“—there she is,” said Layborn, “car’s parked right near the camera, conveniently. In she gets and off she goes. Gets home, insists the stable girl stays overnight, sleeps in the next room, goes outside next morning to ride within sight of the girl… cast-iron alibi.

“Course, like you, we’d already come to the conclusion that if it was murder, it must have been a two-person job.”

“Because of the orange juice?” asked Robin.

“Mostly,” said Layborn. “If Chiswell” (he said the name as it was spelled) “had taken amitriptyline unknowingly, the most likely explanation was that he’d poured himself doctored juice out of a carton in the fridge, but the carton in the bin was undoctored and only had his prints on.”

“Easy to get his prints on small objects once he was dead, though,” said Strike. “Just press his hand onto them.”

“Exactly,” said Layborn, striding over the wall of photographs and pointing at a close-up of the pestle and mortar. “So we went back to this. The way Chiswell’s prints are positioned and the way the powdered residue was sitting there pointed to it being faked, which meant the doctored juice could have been fixed up hours in advance, by somebody who had a key, who knew which anti-depressants the wife was on, that Chiswell’s sense of taste and smell were impaired and that he always drank juice in the mornings. Then all they’d need to do is have the accomplice plant an undoctored juice carton in the bin with his dead handprint on, and take away the one with the amitriptyline residue in it.

“Well, who’s better positioned to know and do all of that, than the missus?” asked Layborn rhetorically. “But here she was, with her cast-iron alibi for time of death, seventy-odd miles away when he was gulping down anti-depressants. Not to mention she’s left that letter, trying to give us a nice clean story: husband already facing bankruptcy and blackmail realizes his wife’s leaving him, which tips him over the edge, so he tops himself.

“But,” said Layborn, pointing at the enlarged picture of the dead Chiswell’s face, stripped of its plastic bag, revealing a deep red scrape on the cheek, “we didn’t like the look of that. We thought from the first that was suspicious. Amitriptyline in overdose can cause agitation as well as sleepiness. That mark looked as though somebody else forced the bag over his head.

“Then there was the open door. The last person in or out didn’t know there was a trick to closing it properly, so it didn’t look like Chiswell was the last person to touch it. Plus, the packaging on the pills being absent—that smelled wrong from the start. Why would Jasper Chiswell get rid of it?” asked Layborn. “Just a few little careless mistakes.”

“It nearly came off,” said Strike. “If only Chiswell had been put to sleep by the amitriptyline as intended, and if they’d thought the thing through right to the finest details—close the door properly, leave the pill packaging in situ—”

“But they didn’t,” said Layborn, “and she’s not smart enough on her own to talk herself out of this.”

“‘I can’t believe this is happening,’” Strike quoted. “She’s consistent. On Saturday night she told us ‘I didn’t think this would happen,’ ‘it didn’t seem real—’”

“Try that in court,” said Wardle quietly.

“Yeah, what were you expecting, love, when you crushed up a load of pills and put them in his orange juice?” said Layborn. “Guilty is as guilty does.”

“Amazing, the lies people can tell themselves when they’re drifting along in the wake of a stronger personality,” said Strike. “I’ll bet you a tenner that when McMurran finally breaks her, Kinvara’ll say they started off hoping Chiswell would kill himself, then trying to pressure him into doing it, and finally reached a point when there didn’t seem much difference between trying to push him into suicide, and putting the pills in his orange juice herself. I notice she’s still trying to push the gallows business as the reason he’d top himself.”

“That was very good work of yours, connecting the dots on the gallows,” admitted Layborn. “We were a bit behind you on that, but it explained a hell of a lot. This is highly confidential,” he added, taking a brown envelope off a nearby desk and tipping out a large photograph, “but we had this from the Foreign Office this morning. As you can see—”

Robin, who had gone to look, half-wished she hadn’t. What was there to be gained, really, from seeing the corpse of what seemed to be a teenage boy, whose eyes had been picked out by carrion birds, and hanging from a gallows in a rubble-strewn street? The boy’s dangling feet were bare. Somebody, Robin guessed, had stolen his trainers.

“The lorry containing the second pair of gallows was hijacked. Government never took delivery and Chiswell never got payment for them. This picture suggests they ended up being used by rebels for extrajudicial killings. This poor lad, Samuel Murape, was in the wrong place at the wrong time. British student, gap year, out there to visit family. It’s not particularly clear,” Layborn said, “but see there, just behind his foot—”

“Yeah, that could be the mark of the white horse,” said Strike.

Robin’s mobile, which was switched to silent, vibrated in her pocket. She was waiting for an important call, but it was only a text from an unknown number.

“It’s nothing,” Robin told Strike, returning the mobile to her pocket.

This was the third message Matthew had left that day.

Urgent situation, my arse.

Tom had probably found out that his fiancée and his good friend had been sleeping together. Maybe Tom was threatening to call Robin, or drop in on the office in Denmark Street, to find out how much she knew. If Matthew thought that constituted an “urgent situation” to Robin, who was currently standing beside multiple pictures of a drugged and suffocated government minister, he was wrong. With an effort, she refocused on the conversation in the incident room.

“… the necklace business,” Layborn was saying to Strike. “Far more convincing story than the one he told us. All that guff about wanting to stop her hurting herself.”

“It was Robin who got him to change his story, not me,” said Strike.

“Ah—well, good work,” Layborn said to Robin, with a hint of patronage. “I thought he was an oily little bastard when I took his initial statement. Cocky. Just out of jail, and all. No bloody remorse for running over that poor woman.”

“How are you getting on with Francesca?” Strike asked. “The girl from the gallery?”

“We managed to get hold of the father in Sri Lanka and he’s not happy. Being quite obstructive, actually,” said Layborn. “He’s trying to buy time to get her lawyered up. Bloody inconvenient, the whole family being abroad. I had to get tough with him over the phone. I can understand why he doesn’t want it all coming out in court, but too bad. Gives you a real insight into the mindset of the upper classes, eh, case like this? One rule for them…”

“On that subject,” said Strike, “I assume you’ve spoken to Aamir Mallik?”

“Yeah, we found him exactly where your boy—Hutchins, is it?—said he was. At his sister’s. He’s got a new job—”

“Oh, I’m glad,” said Robin inadvertently.

“—and he wasn’t overjoyed to have us turning up at first, but he ended up being very frank and helpful. Said he found that disturbed lad—Billy, is it?—on the street, wanting to see his boss, shouting about a dead child, strangled and buried on Chiswell’s land. Took him home with the idea of getting him to hospital, but he asked Geraint Winn’s advice first. Winn was furious. Told him on no account to call an ambulance.”

“Did he, now?” said Strike, frowning.

“From what Mallik’s told us, Winn was worried association with Billy’s story would taint his own credibility. He didn’t want the waters muddied by a psychotic tramp. Blew up at Mallik for taking him into a house belonging to the Winns, told him to turf him out on the street again. Trouble was—”

“Billy wouldn’t go,” said Strike.

“Exactly. Mallik says he was clearly out of his mind, thought he was being held against his will. Curled up in the bathroom most of the time. Anyway,” Layborn took a deep breath, “Mallik’s had enough of covering up for the Winns. He’s confirmed that Winn wasn’t with him on the morning of Chiswell’s death. Winn told Mallik afterwards, when he put pressure on Mallik to lie, he’d had an urgent phone call at 6 a.m. that day, which is why he left the marital home early.”

“And you’ve traced that call?” said Strike.

Layborn picked up the printout of phone records, rifled through them, then handed a couple of marked pages to Strike.

“Here you go. Burner phones,” he said. “We’ve got three different numbers so far. There were probably more. Used once, never used again, untraceable except for the single instance we got on record. Months in the planning.

“A single-use phone was used to contact Winn that morning, and two more were used to call Kinvara Chiswell on separate occasions during the previous weeks. She ‘can’t remember’ who called her, but both times—see there?—she talked to whoever it was for over an hour.”

“What’s Winn got to say for himself?” asked Strike.

“Closed up like an oyster,” said Layborn. “We’re working on him, don’t worry. There are porn stars who’ve been fucked fewer different ways than Geraint W—sorry, love,” he said, grinning, to Robin, who found the apology more offensive than anything Layborn had said. “But you take my point. He might as well tell us everything now. He’s screwed every which w—well,” he said, floundering once more. “What interests me,” he started up again, “is how much the wife knew. Strange woman.”

“In what way?” asked Robin.

“Oh, you know. I think she plays on this a bit,” said Layborn, with a vague gesture towards his eyes. “Very hard to believe she didn’t know what he was up to.”

“Speaking of people not knowing what their other halves are up to,” interposed Strike, who thought he detected a martial glint in Robin’s eye, “how’s it going with our friend Flick?”

“Ah, we’re making very good progress there,” said Layborn. “The parents have been helpful in her case. They’re both lawyers and they’ve been urging her to cooperate. She’s admitted she was Chiswell’s cleaner, that she stole the note and took receipt of the crate of champagne right before Chiswell told her he couldn’t afford her anymore. Says she put it in a cupboard in the kitchen.”

“Who delivered it?”

“She can’t remember. We’ll find out. Courier service, I shouldn’t wonder, booked on another burner phone.”

“And the credit card?”

“That was another good spot of yours,” admitted Layborn. “We didn’t know a credit card had gone missing. We got details through from the bank this morning. The same day Flick’s flatmate realized the card was gone, somebody charged a crate of champagne and bought a hundred quid’s worth of stuff on Amazon, all to be sent to an address in Maida Vale. Nobody took delivery, so it was returned to the depot where it was picked up that afternoon by someone who had the failed delivery notice. We’re trying to locate the staff who can identify the person who collected it and we’re getting a breakdown on what was bought on Amazon, but my money’s on helium, tubing and latex gloves.

“This was all planned months in advance. Months.”

“And that?” Strike asked, pointing to the photocopy of the note in Chiswell’s handwriting, which was lying on the side in its polythene bag. “Has she told you why she nicked it yet?”

“She says she saw ‘Bill’ and thought it meant her boyfriend’s brother. Ironic, really,” said Layborn. “If she hadn’t stolen it, we wouldn’t have cottoned on nearly so fast, would we?”

The “we,” thought Robin, was daring, because it had been Strike who had “cottoned on,” Strike who had finally cracked the significance of Chiswell’s note, as they drove back to London from Chiswell House.

“Robin deserves the bulk of the credit there, too,” said Strike. “She found the thing, she noticed ‘Blanc de Blanc’ and the Grand Vitara. I just pieced it together once it was staring me in the face.”

“Well, we were just behind you,” said Layborn, absentmindedly scratching his belly. “I’m sure we’d have got there.”

Robin’s mobile vibrated in her pocket again: somebody was calling, this time.

“I need to take this. Is there anywhere I can—?”

“Through here,” said Layborn helpfully, opening a side door.

It was a photocopier room, with a small window covered in a Venetian blind. Robin closed the door on the others’ conversation and answered.

“Hi, Sarah.”

“Hi,” said Sarah Shadlock.

She sounded totally unlike the Sarah whom Robin had known for nearly nine years, the confident and bombastic blonde whom Robin had sensed, even in their teens, was hoping that some mischance might befall Matthew’s long-distance relationship with his girlfriend. Always there through the years, giggling at Matthew’s jokes, touching his arm, asking loaded questions about Robin’s relationship with Strike, Sarah had dated other men, settling at last for poor tedious Tom, with his well-paid job and his bald patch, who had put diamonds on Sarah’s finger and in her ears, but never quelled her yen for Matthew Cunliffe.

All her swagger had gone today.

“Well, I’ve asked two experts, but,” she said, sounding fragile and fearful, “and they can’t say for sure, not from a photograph taken on a phone—”

“Well, obviously not,” said Robin coolly. “I said in my text, didn’t I, that I wasn’t expecting a definitive answer? We’re not asking for a firm identification or valuation. All we want to know is whether somebody might have credibly believed—”

“Well, then, yes,” said Sarah. “One of our experts is quite excited about it, actually. One of the old notebooks lists a painting done of a mare with a dead foal, but it’s never been found.”

“What notebooks?”

“Oh, sorry,” said Sarah. She had never sounded so meek, so frightened, in Robin’s vicinity. “Stubbs.”

“And if it is a Stubbs?” asked Robin, turning to look out of the window at the Feathers, a pub where she and Strike had sometimes drunk.

“Well, this is entirely speculative, obviously… but if it’s genuine, if it’s the one he listed in 1760, it could be a lot.”

“Give me a rough estimate.”

“Well, his ‘Gimcrack’ went for—”

“—twenty-two million,” said Robin, feeling suddenly light-headed. “Yes. You said so at our house-warming party.”

Sarah made no answer. Perhaps the mention of the party, where she had brought lilies to her lover’s wife’s house, had scared her.

“So if ‘Mare Mourning’ is a genuine Stubbs—”

“It’d probably make more than ‘Gimcrack’ at auction. It’s a unique subject. Stubbs was an anatomist, as much scientist as artist. If this is a depiction of a lethal white foal, it might be the first recorded instance. It could set records.”

Robin’s mobile buzzed in her hand. Another text had arrived.

“This has been very helpful, Sarah, thanks. You’ll keep this confidential?”

“Yes, of course,” said Sarah. And then, in a rush:

“Robin, listen—”

“No,” said Robin, trying to stay calm. “I’m working a case.”

“—it’s over, it’s finished, Matt’s in pieces—”

“Goodbye, Sarah.”

Robin hung up, then read the text that had just arrived.

Eager as she was to return to the group next door and relay the sensational information she had just received, Robin remained where she stood, temporarily flummoxed by the threat, and texted back:

His response came within seconds, littered with angry typos.

Robin was rereading the message when yet another text arrived, this time with an attachment.

Robin enlarged the attachment, which was a screenshot of a diary item in the Evening Standard.

A mass of uncomfortable feelings jostled inside Robin, of which the dominant ones were panic, anger and mortification at the thought of Matthew speaking to the press in such a way as to leave open, spitefully, the possibility that she and Strike were indeed sleeping together.

She tried to call the number, but it went straight to voicemail. Two seconds later, another angry text appeared.

Angry now, Robin texted:

She could imagine Matthew’s polite smile as the client watched, his smooth “just the office, excuse me,” while he hammered out his furious replies.

Furious, but feeling cornered, Robin typed back:

He texted her directions to a bar in Little Venice. Still shaken, Robin pushed open the door to the incident room. The group was now huddled around a monitor showing a page of Jimmy Knight’s blog, from which Strike was reading aloud:

“… ‘in other words, a single bottle of wine at Le Manoir aux Quat’Saisons can cost more than a single, out-of-work mother receives per week to feed, clothe and house her entire family.’ Now that,” said Strike, “struck me as a weirdly specific choice of restaurant, if he wanted to rant about Tories and their spending. That’s what made me think he’d been there recently. Then Robin tells me ‘Blanc de Blanc’ is the name of one of their suites, but I didn’t put that together as quickly as I should’ve done. It hit me a few hours later.”

“He’s a hell of a bloody hypocrite on top of everything else, isn’t he?” said Wardle, who was standing, arms folded, behind Strike.

“You’ve looked in Woolstone?” Strike asked.

“The shithole in Charlemont Road, Woolstone, everywhere,” said Layborn, “but don’t worry. We’ve got a line on one of his girlfriends down in Dulwich. Checking there right now. With luck, we’ll have him in custody tonight.”

Layborn now noticed Robin, standing with her phone in her hand.

“I know you’ve already got people looking at it,” she told Layborn, “but I’ve got a contact at Christie’s. I sent her the picture of ‘Mare Mourning’ and she’s just called me back. According to one of their experts, it might be a Stubbs.”

“Even I’ve heard of Stubbs,” Layborn said.

“What would it be worth, if it is?” Wardle asked.

“My contact thinks upwards of twenty-two million.”

Wardle whistled. Layborn said, “Fuck me.”

“Doesn’t matter to us what it’s worth,” Strike reminded them all. “What matters is whether somebody might’ve spotted its potential value.”

“Twenty-two fucking million,” said Wardle, “is a hell of a motive.”

“Cormoran,” said Robin, picking her jacket off the back of the chair where she’d left it, “could I have a quick word outside? I’m going to have to leave, sorry,” she said to the others.

“Everything OK?” Strike asked, as they re-entered the corridor together and Robin had closed the door on the group of police.

“Yes,” said Robin, and then, “Well—not really. Maybe,” she said, handing him her phone, “you’d better just read this.”

Frowning, Strike scrolled slowly through the interchange between Robin and Matthew, including the Evening Standard clip.

“You’re going to meet him?”

“I’ve got to. This must be why Mitch Patterson’s sniffing around. If Matthew fans the flames with the press, which he’s more than capable of doing… They’re already excited about you and—”

“Forget me and Charlotte,” he said roughly, “that was twenty minutes that she coerced me into. He’s trying to coerce you—”

“I know he is,” said Robin, “but I have got to talk to him sooner or later. Most of my stuff’s still in Albury Street. We’ve still got a joint bank account.”

“D’you want me to come?”

Touched, Robin said:

“Thanks, but I don’t think that would help.”

“Then ring me later, will you? Let me know what happened.”

“I will,” she promised.

She headed off alone towards the lifts. She didn’t even notice who had just walked past her in the opposite direction until somebody said, “Bobbi?”

Robin turned. There stood Flick Purdue, returning from the bathroom with a policewoman, who seemed to have escorted her there. Like Kinvara, Flick had cried away her makeup. She appeared small and shrunken in a white shirt that Robin suspected her parents had insisted she wear, rather than her Hezbollah T-shirt.

“It’s Robin. How are you, Flick?”

Flick seemed to be struggling with ideas too monstrous to utter.

“I hope you’re cooperating,” said Robin. “Tell them everything, won’t you?”

She thought she saw a tiny shake of the head, an instinctive defiance, the last embers of loyalty not yet extinguished, even in the trouble Flick found herself.

“You must,” said Robin quietly. “He’d have killed you next, Flick. You knew too much.”