A whining wasp zigzagged from inner to outer rooms of Strike’s office, passing between the two windows that were flung open to admit the fume-laden evening air. Barclay waved the insect away with the takeaway menu that had just arrived with a large delivery of Chinese food. Robin peeled lids off the cartons and laid them out on her desk. Over by the kettle, Strike was trying to find a third fork.

Matthew had been surprisingly accommodating when Robin had called him from Charing Cross Road three-quarters of an hour previously, to say that she needed to meet Strike and Barclay, and was likely to be back late.

“Fine,” he had said, “Tom wants to go for a curry, anyway. I’ll see you at home.”

“How was today?” Robin asked, before he could hang up. “The office out in…”

Her mind went blank.

“Barnet,” he said. “Games developer. Yeah, it was all right. How was yours?”

“Not bad,” said Robin.

Matthew was so determinedly uninterested in the details of the Chiswell job after their many arguments about it that there seemed no point in telling him where she had been, who she was impersonating, or what had happened that day. After they had said goodbye, Robin walked on through meandering tourists and Friday night drinkers, knowing that a casual listener would have taken the conversation to be that of two people connected merely by proximity or circumstance, with no particular liking for each other.

“Want a beer?” Strike asked her, holding up a four pack of Tennent’s.

“Yes, please,” said Robin.

She was still wearing her short black dress and lace-up boots, but had tied back her chalked hair, cleaned her face of its thick makeup and removed her dark lenses. Seeing Strike’s face in a patch of evening sunlight, she thought he looked unwell. There were deeper lines than usual around his mouth and across his forehead, lines etched there, she suspected, by grinding, daily pain. He was also moving awkwardly, using his upper body to turn and trying to disguise his limp as he returned to her desk with the beer.

“What’ve you been up to today?” she asked Strike, as Barclay heaped his plate with food.

“Following Geraint Winn. He’s holed up in a miserable B&B five minutes away from the marital home. He led me all the way into central London and back to Bermondsey again.”

“Risky, following him,” commented Robin. “He knows what you look like.”

“All three of us could’ve been behind him and he wouldn’t have noticed. He’s lost about a stone since I last saw him.”

“What did he do?”

“Went to eat in a place right by the Commons, called the Cellarium. No windows, like a crypt.”

“Sounds cheerful,” said Barclay, settling down on the fake leather sofa and starting on his sweet and sour pork balls.

“He’s like a sad homing pigeon,” said Strike, tipping the whole tub of Singapore noodles onto his own plate, “returning to the place of his former glories with the tourists. Then we went to King’s Cross.”

Robin paused in the act of helping herself to beansprouts.

“Blow job in a dark stairwell,” said Strike matter-of-factly.

“Eurgh,” muttered Robin, continuing to help herself to food.

“Did ye see it, aye?” asked Barclay with interest.

“Back view. Elbowed my way through the front door, then backed out with apologies. He was in no state to recognize me. After that, he bought himself some new socks from Asda and went back to his B&B.”

“There are worse days out,” said Barclay, who had already eaten half the food on his plate. Catching Robin’s eye, he said through a mouthful, “Wife wants me home by half eight.”

“All right, Robin,” said Strike, lowering himself gingerly onto his own desk chair, which he had brought through to the outer office, “let’s hear what Jimmy and Flick had to say to each other when they thought no one was listening.”

He opened a notebook and took a pen from the pot on her desk, leaving his left hand free to fork Singapore noodles into his mouth. Still chewing vigorously, Barclay leaned forwards on the sofa, interested. Robin placed her mobile face up on the desk and pressed “play.”

For a moment there was no sound except faint footsteps, which were Robin’s, leaving the Wiccan’s shop earlier in search of lunch.

“I thought you were here on your own?” said Jimmy’s voice, faint but clear.

“She’s having a day’s trial,” said Flick. “Where’s Sam?”

“I told him I’ll meet him at yours later. Right, where’s your bag?”

“Jimmy, I haven’t—”

“Maybe you picked it up by mistake.”

More footsteps, a scraping of wood and leather, clattering, thunks and furtive rustlings.

“This is a fucking tip.”

“I haven’t got it, how many more times? And you’ve got no right to search that without my—”

“This is serious. I had it in my wallet. Where’s it gone?”

“You’ve dropped it somewhere, haven’t you?”

“Or someone’s taken it.”

“Why would I take it?”

“Insurance policy.”

“That’s a hell of an—”

“But if that’s what you’re thinking, you wanna remember, you fucking nicked it, so it incriminates you as much as me. More.”

“I was only there in the first place because of you, Jimmy!”

“Oh, that’s going to be the story, is it? Nobody bloody made you. You’re the one who started all this, remember.”

“Yeah and I wish I hadn’t, now!”

“Too late for that. I want that paper back and so should you. It proves we had access to his place.”

“You mean it proves a connection between him and Bill—ouch!”

“Oh, fuck off, that didn’t hurt! You demean women who really are knocked around, playing the victim. I’m not kidding, now. If you’ve taken it—”

“Don’t threaten me—”

“What’re you going to do, run off to Mummy and Daddy? How’re they going to feel when they find out what their little girl’s been up to?”

Flick’s rapid breathing now became sobs.

“You nicked money from him, and all,” said Jimmy.

“You thought it was a laugh at the time, you said he deserved it—”

“Try that defense in court, see how far it gets you. If you try and save yourself by throwing me under the bus, I won’t have any fucking problem telling the pigs you were in this thing all the way. So if that bit of paper turns up somewhere I don’t want it to go—”

“I haven’t got it, I don’t know where it is!”

“—you’ve been fucking warned. Give me your front door key.”

“What? Why?”

“Because I’m going over to that shithole you call a flat right now and I’m searching it with Sam.”

“You’re not going over there without me—”

“Why not? Got another Indian waiter sleeping off his hangover there, have you?”

“I never—”

“I don’t give a shit,” said Jimmy. “Screw whoever you like. Give me your key. Give it me.”

More footsteps; a tinkling of keys. The sound of Jimmy walking away and then a cascade of sobs that continued until Robin pressed pause.

“She cried until the shop owner came back,” said Robin, “which was just before I did, and she hardly spoke this afternoon. I tried to walk back to the Tube with her, but she shook me off. Hopefully she’ll be in a more talkative mood tomorrow.”

“So, did you and Jimmy search her flat?” Strike asked Barclay.

“Aye. Books, drawers, under her mattress. Nothing.”

“What exactly did he say you were looking for?”

“‘Bit o’ paper wi’ handwriting an’ Billy’s name on,’ he says. ‘I had it in me wallet and it’s gone.’ Claims it’s somethin’ tae do with a drugs deal. He thinks I’m some ned who’ll believe anythin’.”

Strike put down his pen, swallowed a large mouthful of noodles and said:

“Well, I don’t know about you two, but what jumps out at me is ‘it proves we had access.’”

“I think I might know a bit more about that,” said Robin, who had so far successfully concealed her excitement about what she was about to reveal. “I found out today that Flick can speak a bit of Polish, and we know she stole cash from her previous place of work. What if—?”

“‘I do that cleaning,’” said Strike, suddenly. “That’s what she said to Jimmy, on the march, when I was following them! ‘I do that cleaning, and it’s disgusting’… Bloody hell—you think she was—?”

“Chiswell’s Polish cleaner,” said Robin, determined not to be robbed of her moment of triumph. “Yes. I do.”

Barclay was continuing to shovel pork balls into his mouth, though his eyes were suitably surprised.

“If that’s true, it changes bloody everything,” said Strike. “She’d have had access, been able to snoop around, take stuff into the house—”

“How’d she find out he wanted a cleaner?” asked Barclay.

“Must’ve seen the card he put in a newsagent’s window.”

“They live miles apart. She’s in Hackney.”

“Maybe Jimmy spotted it, snooping around Ebury Street, trying to collect his blackmail money,” suggested Robin, but Strike was now frowning.

“But that’s back to front. If she found out about the blackmailable offense when she was a cleaner, her employment must’ve pre-dated Jimmy trying to collect money.”

“All right, maybe Jimmy didn’t tip her off. Maybe they found out he wanted a cleaner while they were trying to dig dirt on him in general.”

“So they could run an exposé on the Real Socialist Party website?” suggested Barclay. “That’d reach a good four or five people.”

Strike snorted in amusement.

“Main point is,” he said, “this piece of paper’s got Jimmy very worried.”

Barclay speared his last pork ball and stuck it in his mouth. “Flick’s taken it,” he said thickly. “I guarantee it.”

“Why are you so sure?” asked Robin.

“She wants somethin’ over him,” said Barclay, getting up to take his empty plate over to the sink. “Only reason he’s keepin’ her around is because she knows too much. He told me the other day he’d be happy tae get shot of her if he could. I asked why he couldnae just dump her. He didnae answer.”

“Maybe she’s destroyed it, if it’s so incriminating?” suggested Robin.

“I don’t think so,” said Strike. “She’s a lawyer’s daughter, she’s not going to destroy evidence. Something like that paper could be valuable, if the shit hits the fan and she decides she’s going to cooperate with the police.”

Barclay returned to the sofa and picked up his beer.

“How’s Billy?” Robin asked him, getting started at last on her own cooling meal.

“Poor wee bastard,” said Barclay. “Skin and bone. The traffic cops caught him when he jumped a Tube barrier. He tried tae batter them, ended up bein’ sectioned. The doctors say he’s got delusions o’ persecution. At first he thought he was bein’ chased by the government and the medical staff were all part o’ some giant conspiracy, but now he’s back on his medication he’s a wee bit more rational.

“Jimmy wanted tae take him home there and then, but the docs werenae gonna let that happen. What’s really pissin’ Jimmy off,” said Barclay, pausing to finish his can of Tennent’s, “is Billy’s still obsessed wi’ Strike. Keeps askin’ for him. The doctors think it’s part o’ his delusion, that he’s latched ontae the famous detective as part of his fantasy, like: the only person he can really trust. Couldnae tell them he and Strike have met. Not wi’ Jimmy standin’ there telling them it’s all a load o’ pish.

“The medics don’t want anyone near him except family, and they’re no keen on Jimmy any more, neither, not after he tried tae persuade Billy he’s well enough to go home.”

Barclay crushed his beer can in his hand and checked his watch.

“Gotta go, Strike.”

“Yeah, all right,” said Strike. “Thanks for staying. Thought it would be good to have a joint debrief.”

“Nae bother.”

With a wave to Robin, Barclay departed. Strike bent to pick up his own beer off the floor and winced.

“You all right?” asked Robin, who was helping herself to more prawn crackers.

“Fine,” he said, straightening up again. “I did a lot of walking again today, and I could have done without the fight yesterday.”

“Fight? What fight?” asked Robin.

“Aamir Mallik.”

“What!”

“Don’t worry. I didn’t hurt him. Much.”

“You didn’t tell me the argument got physical!”

“I wanted to do it in person, so I could enjoy you looking at me like I’m a complete bastard,” said Strike. “How about a bit of sympathy for your one-legged partner?”

“You’re an ex-boxer!” said Robin. “And he probably weighs about nine stone soaking wet!”

“He came at me with a lamp.”

“Aamir did?”

She couldn’t imagine the reserved, meticulous man she had known in the House of Commons using physical violence against anyone.

“Yeah. I was pushing him about Chiswell’s ‘man of your habits’ comment and he snapped. If it makes you feel any better, I don’t feel good about it,” said Strike. “Hang on a minute. Need a pee.”

He pulled himself awkwardly out of the chair and departed for the bathroom on the landing. As she heard the door close, Strike’s mobile, which was charging on top of the filing cabinet beside Robin’s desk, rang. She got up to check it and saw, through the cracked and sellotaped screen, the name “Lorelei.” Wondering whether to answer it, Robin hesitated too long and the call went to voicemail. Just as she was about to sit down again, a small ping declared that a text arrived.

Robin heard the bang of the bathroom door outside and stumbled hastily back to her chair. Strike limped back inside the room, lowered himself into his chair and picked up his noodles.

“Your phone just rang,” said Robin. “I didn’t pick up—”

“Chuck it over,” said Strike.

She did so. He read the text with no change of expression, muted the phone and put it in his pocket.

“What were we saying?”

“That you didn’t feel good about the fight—”

“I feel fine about the fight,” Strike corrected her. “If I hadn’t defended myself I’d have a face full of stitches.”

He pronged a forkful of noodles.

“The bit I don’t feel great about is when I told him I know he’s been ostracized by his family, barring one sister who’s still talking to him. It’s all on Facebook. It was when I mentioned his family dropping him that I nearly got my head taken off with a table lamp.”

“Maybe they’re upset because they think he’s with Della?” suggested Robin as Strike chewed his noodles.

He shrugged and made an expression indicative of “maybe,” swallowed, and said, “Has it occurred to you that Aamir is literally the only person connected with this case who’s got a motive? Chiswell threatened him, presumably with exposure. ‘A man of your habits.’ ‘Lachesis knew when everyone’s time was up.’”

“What happened to ‘forget about motive, concentrate on means’?”

“Yeah, yeah,” said Strike wearily. He set aside his plate, from which he had eaten nearly all the noodles, took out his cigarettes and lighter, and sat up a little straighter. “OK, let’s focus on means.

“Who had access to the house, to anti-depressants and helium? Who knew Jasper Chiswell’s habits well enough to be sure he’d drink his orange juice that morning? Who had a key, or, who would he have trusted enough to let in in the early hours of the morning?”

“Members of his family.”

“Right,” said Strike, as his lighter flared, “but we know Kinvara, Fizzy, Izzy and Torquil can’t have done it, which leaves us with Raphael and his story of being ordered down to Woolstone that morning.”

“You really think he could have killed his father then driven coolly down to Woolstone to wait with Kinvara until the police arrived?”

“Forget psychology or probability: we’re considering opportunity,” said Strike, blowing out a long jet of smoke. “Nothing I’ve heard so far precludes Raphael being at Ebury Street at six in the morning. I know what you’re going to say,” he forestalled her, “but it wouldn’t be the first time a phone call had been faked by a killer. He could have called his own mobile with Chiswell’s to make it seem as though his father had ordered him down to Woolstone.”

“Which means that either Chiswell didn’t have a passcode on his mobile, or that Raphael knew it.”

“Good point. That needs checking.”

Clicking out the nib of his pen, Strike made a note on his pad. As he did it, he wondered whether Robin’s husband, who had previously deleted her call history without her knowledge, knew her current passcode. These small matters of trust were often powerful indicators of the strength of a relationship.

“There’s another logistical problem if Raphael was the killer,” Robin said. “He didn’t have a key, and if his father let him in, it would mean Chiswell was awake and conscious while Raphael pounded up anti-depressants in the kitchen.”

“Another good point,” said Strike, “but the pounding up of the pills has to be explained away with all of our suspects.

“Take Flick. If she was posing as the cleaner, she probably knew the house in Ebury Street better than most of the family. Loads of opportunities to poke around, and she had a restricted key for a while. They’re hard to get copied, but let’s say she managed it, so she could still let herself in and out of the house whenever she fancied.

“She creeps in in the early hours to doctor the orange juice, but crushing pills in a pestle and mortar is a noisy job—”

“—unless,” said Robin, “she brought the pills already crushed up, in a bag or something, and dusted them around the pestle and mortar to make it look as though Chiswell had done it.”

“OK, but we still need to explain why there were no traces of amitriptyline in the empty orange juice carton in the bin. Raphael could plausibly have handed his father a glass of juice—”

“—except that Chiswell’s prints were the only ones on there—”

“—but would Chiswell not find it odd to come downstairs in the morning to a pre-poured glass of juice? Would you drink a glass of something you hadn’t poured, and which appeared mysteriously in what you thought was an empty house?”

Down in Denmark Street, a group of young women’s voices rose over the constant swish and rumble of traffic, singing Rihanna’s “Where Have You Been?”

“Where have you been? All my life, all my life…”

“Maybe it was suicide,” said Robin.

“That attitude won’t get the bills paid,” said Strike, tapping his cigarette ash onto his plate. “Come on, people who had the means to get into Ebury Street that day: Raphael, Flick—”

“—and Jimmy,” said Robin. “Everything that applies to Flick applies to him, because she would’ve been able to give him all the information she had about Chiswell’s habits and his house, and given him her copied key.”

“Correct. So those are three people we know could have got in that morning,” said Strike, “but this took much more than simply being able to get in through the door. The killer also had to know which anti-depressants Kinvara was taking, and arrange for the helium canister and rubber tubing to be there, which suggests close contact with the Chiswells, access to the house to get the stuff inside, or insider knowledge of the fact that the helium and tubing were already in there.”

“As far as we know, Raphael hadn’t been in Ebury Street lately and wasn’t on terms with Kinvara to know what pills she was taking, though I suppose his father might have mentioned it to him,” said Robin. “Judged on opportunity alone, the Winns and Aamir seem to be ruled out… so, assuming she was the cleaner, Jimmy and Flick go to the top of our suspect list.”

Strike heaved a sigh and closed his eyes.

“Bollocks to it,” he muttered, as he passed a hand across his face, “I keep circling back to motive.”

Opening his eyes again, he stubbed out his cigarette on his dinner plate and immediately lit another one.

“I’m not surprised MI5 are interested, because there’s no obvious gain here. Oliver was right—blackmailers don’t generally kill their victims, it’s the other way around. Hatred’s a picturesque idea, but a hot-blooded hate killing is a hammer or a lamp to the head, not a meticulously planned fake suicide. If it was murder, it was more like a clinical execution, planned in every detail. Why? What did the killer get out of it? Which also makes me wonder, why then? Why did Chiswell die then?

“It was surely in Jimmy and Flick’s best interests for Chiswell to stay alive until they could produce evidence that forced him to come across with the money they wanted. Same with Raphael: he’d been written out of the will, but his relationship with his father was showing some signs of improvement. It was in his interest for his father to stay alive.

“But Chiswell had covertly threatened Aamir with exposure of something unspecified, but probably sexual, given the Catullus quotation, and he’d recently come into possession of information about the Winns’ dodgy charity. We shouldn’t forget that Geraint Winn wasn’t really a blackmailer: he didn’t want money, he wanted Chiswell’s resignation and disgrace. Is it beyond the realms of possibility that Winn or Mallik took a different kind of revenge when they realized the first plan had failed?”

Strike dragged heavily on his cigarette and said:

“We’re missing something, Robin. The thing that ties all this together.”

“Maybe it doesn’t tie together,” said Robin. “That’s life, isn’t it? We’ve got a group of people who all had their own personal tribulations and secrets. Some of them had reason not to like Chiswell, to resent him, but that doesn’t mean it all joins up neatly. Some of it must be irrelevant.”

“There’s still something we don’t know.”

“There’s a lot we don’t—”

“No, something big, something… fundamental. I can smell it. It keeps almost showing itself. Why did Chiswell say he might have more work for us after he’d scuppered Winn and Knight?”

“I don’t know,” said Robin.

“‘One by one, they trip themselves up,’” Strike quoted. “Who’d tripped themselves up?”

“Geraint Winn. I’d just told him about the missing money from the charity.”

“Chiswell had been on the phone, trying to find a money clip, you said. A money clip that belonged to Freddie.”

“That’s right,” said Robin.

“Freddie,” repeated Strike, scratching his chin.

And for a moment he was back in the communal TV room of a German military hospital, with the television muted in the corner and copies of the Army Times lying on a low table. The young lieutenant who had witnessed Freddie Chiswell’s death had been sitting there alone when Strike found him, wheelchair-bound, a Taliban bullet still lodged in his spine.

“… the convoy stopped, Major Chiswell told me to get out, see what was going on. I told him I could see movement up on the ridge. He told me to fucking well do as I was told.

“I hadn’t gone more than a couple of feet when I got the bullet in the back. The last thing I remember was him yelling out of the lorry at me. Then the sniper took the top of his head off.”

The lieutenant had asked Strike for a cigarette. He wasn’t supposed to be smoking, but Strike had given him the half pack he had on him.

“Chiswell was a cunt,” said the young man in the wheelchair.

In Strike’s imagination he saw tall, blond Freddie swaggering up a country lane, slumming it with Jimmy Knight and his mates. He saw Freddie in fencing garb, out on the piste, watched by the indistinct figure of Rhiannon Winn, who was perhaps already entertaining suicidal thoughts.

Disliked by his soldiers, revered by his father: could Freddie be the thing that Strike sought, the element that tied everything together, that connected two blackmailers and the story of a strangled child? But the notion seemed to dissolve as he examined it, and the diverse strands of the investigation fell apart once more, stubbornly unconnected.

“I want to know what the photographs from the Foreign Office show,” said Strike aloud, his eyes on the purpling sky beyond the office window. “I want to know who hacked the Uffington white horse onto the back of Aamir Mallik’s bathroom door, and I want to know why there was a cross in the ground on the exact spot Billy said a kid was buried.”

“Well,” said Robin, standing up and beginning to clear away the debris of their Chinese takeaway, “nobody ever said you weren’t ambitious.”

“Leave that. I’ll do it. You need to get home.”

I don’t want to go home.

“It won’t take long. What are you up to tomorrow?”

“Got an afternoon appointment with Chiswell’s art dealer friend, Drummond.”

Having rinsed off the plates and cutlery, Robin took her handbag down from the peg where she’d hung it, then turned back. Strike tended to rebuff expressions of concern, but she had to say it.

“No offense, but you look terrible. Maybe rest your leg before you have to go out again? See you soon.”

She left before Strike could answer. He sat lost in thought until, finally, he knew he must begin the painful journey back upstairs to his attic flat. Having heaved himself upright again, he closed the windows, turned off the lights and locked up the office.

As he placed his false foot on the bottom stair to the floor above, his phone rang again. He knew, without checking, that it was Lorelei. She wasn’t about to let him go without at least attempting to hurt him as badly as he had hurt her. Slowly, carefully, keeping his weight off his prosthesis as much as was practical, Strike climbed the stairs to bed.