The first, admissible, reason was her ongoing divorce, which was becoming more contentious by the week. Following Robin’s discovery of her estranged husband’s affair, they’d had one last cold and bitter meeting, coincidentally in a Pizza Express near Matthew’s place of work, where they’d agreed to seek a no-fault divorce following a two-year separation. Robin was too honest not to admit that she, too, bore responsibility for the failure of their relationship. Matthew might have been unfaithful, but she knew that she’d never fully committed to the marriage, that she’d prioritized her job over Matthew on almost every occasion and that, by the end, she had been waiting for a reason to leave. The affair had been a shock, but a release, too.

However, during the twelve months that had elapsed since her pizza with Matthew, Robin had come to realize that far from seeking a “no-fault” resolution, her ex-husband saw the end of the marriage as entirely Robin’s responsibility and was determined to make her pay, both emotionally and financially, for her offense. The joint bank account, which held the proceeds of the sale of their old house, had been frozen while the lawyers wrangled over how much Robin could reasonably expect when she had been earning so much less than Matthew, and had—it had been strongly hinted in the last letter—married him purely with a view to obtaining a pecuniary advantage she could never have achieved alone.

Every letter from Matthew’s lawyer caused Robin additional stress, rage and misery. She hadn’t needed her own lawyer to point out that Matthew appeared to be trying to force her to spend money she didn’t have on legal wrangling, to run down the clock and her resources until she walked away with as close to nothing as he could manage.

“I’ve never known a childless divorce be so contentious,” her lawyer had told her, words that brought no comfort.

Matthew continued to occupy almost as much space in Robin’s head as when they’d been married. She thought she could read his thoughts across the miles and silence that separated them in their widely divergent new lives. He’d always been a bad loser. He had to emerge from this embarrassingly short marriage the winner, by walking away with all the money, and stigmatizing Robin as the sole reason for its failure.

All of this was ample reason for her present mood, of course, but then there was the other reason, the one that was inadmissible, that Robin was annoyed with herself for fretting about.

It had happened the previous day, at the office. Saul Morris, the agency’s newest subcontractor, was owed his month’s expenses, so, after seeing Tufty safely back into the marital home in Windsor, Robin had driven back to Denmark Street to pay Saul.

Morris had been working for the agency for six weeks. He was an ex-police officer, an undeniably handsome man, with black hair and bright blue eyes, though something about him set Robin’s teeth on edge. He had a habit of softening his voice when he spoke to her; arch asides and over-personal comments peppered their most mundane interactions, and no double entendre went unmarked if Morris was in the room. Robin rued the day when he’d found out that both of them were currently going through divorces, because he seemed to think this gave him fertile new ground for assumed intimacy.

She’d hoped to get back from Windsor before Pat Chauncey, the agency’s new office manager, left, but it was ten past six by the time Robin climbed the stairs and found Morris waiting for her outside the locked door.

“Sorry,” Robin said, “traffic was awful.”

She’d paid Morris back in cash from the new safe, then told him briskly she needed to get home, but he clung on like gum stuck in her hair, telling her all about his ex-wife’s latest late-night texts. Robin tried to unite politeness and coolness until the phone rang on her old desk. She’d ordinarily have let it go to voicemail, but so keen was she to curtail Morris’s conversation that she said,

“I’ve got to get this, sorry. Have a nice evening,” and picked up the receiver.

“Strike Detective Agency, Robin speaking.”

“Hi, Robin,” said a slightly husky female voice. “Is the boss there?”

Given that Robin had only spoken to Charlotte Campbell once, three years previously, it was perhaps surprising that she’d known instantly who was on the line. Robin had analyzed these few words of Charlotte’s to a perhaps ludicrous degree since. Robin had detected an undertone of laughter, as though Charlotte found Robin amusing. The easy use of Robin’s first name and the description of Strike as “the boss” had also come in for their share of rumination.

“No, I’m afraid not,” Robin had said, reaching for a pen while her heart beat a little faster. “Can I take a message?”

“Could you ask him to call Charlotte Campbell? I’ve got something he wants. He knows my number.”

“Will do,” said Robin.

“Thanks very much,” Charlotte had said, still sounding amused. “Bye, then.”

Robin had dutifully written down “Charlotte Campbell called, has something for you” and placed the message on Strike’s desk.

Charlotte was Strike’s ex-fiancée. Their engagement had been terminated three years previously, on the very day that Robin had come to work at the agency as a temp. Though Strike was far from communicative on the subject, Robin knew that they’d been together for sixteen years (“on and off,” as Strike tended to emphasize, because the relationship had faltered many times before its final termination), that Charlotte had become engaged to her present husband just two weeks after Strike had left her and that Charlotte was now the mother of twins.

But this wasn’t all Robin knew, because after leaving her husband, Robin had spent five weeks living in the spare room of Nick and Ilsa Herbert, who were two of Strike’s best friends. Robin and Ilsa had struck up their own friendship during that time, and still met regularly for drinks and coffees. Ilsa made very little secret of the fact that she hoped and believed that Strike and Robin would one day, and preferably soon, realize that they were “made for each other.” Although Robin regularly asked Ilsa to desist from her broad hints, asserting that she and Strike were perfectly happy with a friendship and working relationship, Ilsa remained cheerfully unconvinced.

Robin was very fond of Ilsa, but her pleas for her new friend to forget any idea of matchmaking between herself and Strike were genuine. She was mortified by the thought that Strike might think she herself was complicit in Ilsa’s regular attempts to engineer foursomes that increasingly had the appearance of double dates. Strike had declined the last two proposed outings of this type and, while the agency’s current workload certainly made any kind of social life difficult, Robin had the uncomfortable feeling that he was well aware of Ilsa’s ulterior motive. Looking back on her own brief married life, Robin was sure she’d never been guilty of treating single people as she now found herself treated by Ilsa: with a cheerful lack of concern for their sensibilities, and sometimes ham-fisted attempts to manage their love lives.

One of the ways in which Ilsa attempted to draw Robin out on the subject of Strike was to tell her all about Charlotte, and here, Robin felt guilty, because she rarely shut the Charlotte conversations down, even though she never left one of them without feeling as though she had just gorged on junk food: uncomfortable, and wishing she could resist the craving for more.

She knew, for instance, about the many me-or-the-army ultimatums, two of the suicide attempts (“The one on Arran wasn’t a proper one,” said Ilsa scathingly. “Pure manipulation”) and about the ten days’ enforced stay in the psychiatric clinic. She’d heard stories that Ilsa gave titles like cheap thrillers: the Night of the Bread Knife, the Incident of the Black Lace Dress and the Blood-Stained Note. She knew that in Ilsa’s opinion, Charlotte was bad, not mad, and that the worst rows Ilsa and her husband Nick had ever had were on the subject of Charlotte, “and she’d have bloody loved knowing that, too,” Ilsa had added.

And now Charlotte was phoning the office, asking Strike to call her back, and Robin, sitting outside the Pizza Express, hungry and exhausted, was pondering the phone call yet again, much as a tongue probes a mouth ulcer. If she was phoning the office, Charlotte clearly wasn’t aware that Strike was in Cornwall with his terminally ill aunt, which didn’t suggest regular contact between them. On the other hand, Charlotte’s slightly amused tone had seemed to hint at an alliance between herself and Strike.

Robin’s mobile, which was lying on the passenger seat beside the bag of almonds, buzzed. Glad of any distraction, she picked it up and saw a text message from Strike.

Are you awake?

Robin texted back:

No

As she’d expected, the mobile rang immediately.

“Well, you shouldn’t be,” said Strike, without preamble. “You must be knackered. What’s it been, three weeks straight on Tufty?”

“I’m still on him.”

“What?” said Strike, sounding displeased. “You’re in Glasgow? Where’s Barclay?”

“In Glasgow. He was ready in position, but Tufty didn’t get on the plane. He drove down to Torquay instead. He’s having pizza right now. I’m outside the restaurant.”

“The hell’s he doing in Torquay, when the mistress is in Scotland?”

“Visiting his original family,” said Robin, wishing she could see Strike’s face as she delivered the next bit of news. “He’s a bigamist.”