And when, later in the song, Mitchell asked: “what are you going to do now? You got no one to give your love to,” tears started in Robin’s eyes. Not a mile from where she lay, Matthew and Sarah would be lying in bed in her ex-father-in-law’s spare room, and here was Robin, alone again in a room that for her would forever have a hint of prison cell about it. This was where she had spent months after leaving university, pinioned within four walls by her own memories of a man in a gorilla mask, and the worst twenty minutes of her life.

Since arriving home, everyone in the house had been keen to accompany her into Masham, “because you shouldn’t have to hide.” The implication, no matter their kind intention, was that it would be a natural response for a woman whose ex-husband had found a new partner to hide. There was shame in being single.

But listening to Court and Spark, Robin thought that it was perfectly true that she was traveling in a different direction to anyone she knew. She was fighting her way back to the person she should have been before a man in a mask reached for her from the darkness beneath a stairwell. The reason nobody else understood was that they assumed that her true self was to be the wife Matthew Cunliffe had wanted: a woman who worked quietly in HR and stayed home safely after dark. They didn’t realize that that woman had been the result of those twenty minutes, and that the authentic Robin might never have emerged if she hadn’t been sent, by mistake, to a shabby office in Denmark Street.

With a strange sense of having spent her sleepless hours fruitfully, Robin turned off her iPod. Four o’clock on Boxing Day morning and the house was silent at last. Robin took out her earbuds, rolled over and managed to fall asleep.

Two hours later, Annabel woke again, and this time, Robin got up and crept downstairs, bare-footed, to the big wooden table beside the Aga, carrying her notebook, her laptop and her phone.

It was pleasant to have the kitchen to herself. The garden beyond the window, covered in a hard frost, was dark blue and silver in the winter pre-dawn. Setting her laptop and phone on the table, she greeted Rowntree, who was too arthritic these days for early morning frolicking, but wagged his tail lazily from his basket beside the radiator. She made herself a cup of tea, then took a seat at the table and opened her laptop.

She hadn’t yet read Strike’s document summarizing the horoscope notes, which had arrived while she was busy helping her mother cook Christmas lunch. Robin had been adding the Brussels sprouts to the steamer when she saw, out of the corner of her eye, the notification on her phone, which was charging on one of the few power points that wasn’t taken up by some piece of baby equipment: bottle steril­izer, baby alarm or breast pump. Seeing Strike’s name, her heart had momentarily lifted, because she was sure that she was about to read thanks for the gift of the Tom Waits DVD, and the fact that he’d emailed on Christmas Day was an indicator of friendship such as she had perhaps never received from him.

However, when she opened the email she simply read:

FYI: summary of Talbot’s horoscope notes and action points.

Robin knew her face must have fallen when she looked up and saw Linda watching her.

“Bad news?”

“No, just Strike.”

“On Christmas Day?” said Linda sharply.

And Robin had realized in that instant that Geoffrey, her ex-father-in-law, must have been spreading it around Masham that if Matthew had been unfaithful, it was only after being heinously betrayed himself. She read the truth in her mother’s face, and in Jenny’s sudden interest in Annabel, whom she was jiggling in her arms, and in the sharp look flung at her by Jonathan, her youngest brother, who was tipping bottled cranberry sauce into a dish.

“It’s work,” Robin had said coldly. Each of her silent accusers had returned hastily to their tasks.

It was, therefore, with very mixed feelings toward the author that Robin now settled down to read Strike’s document. Emailing her on Christmas Day had felt reproachful, as though she’d let him down by going back to Masham instead of remaining in London and single-handedly running the agency while he, Barclay and Morris were down with flu. Moreover, if he was going to email at all on Christmas Day, some kind of personal message might be seen as common politeness. Perhaps he’d simply treated her Christmas present with the same indifference she’d treated his.

Robin had just read to the bottom of “Possible leads” and was digesting the idea that a professional gangster had been, on at least one occasion, in close proximity to Margot Bamborough, when the kitchen door opened, admitting baby Annabel’s distant wails. Linda entered the room, wearing a dressing gown and slippers.

“What are you doing down here?” she asked, sounding disapproving, as she crossed to the kettle.

Robin tried not to show how irked she felt. She’d spent the last few days smiling until her face ached, helping as much as was physically possible, admiring baby Annabel until she doubted that a pore had been left unpraised; she’d joined in charades and poured drinks and watched films and unwrapped chocolates or cracked nuts for Jenny, who was constantly pinned to the sofa by the demands of breastfeeding. She’d shown an intelligent and sympathetic interest in Jonathan’s university friends’ exploits; she’d listened to her father’s opinions on David Cameron’s agricultural policy and she’d noticed, but shown no resentment about, the fact that not a single member of her family had asked what she was doing at work. Was she not allowed to sit quietly in the kitchen for half an hour, while Annabel rendered sleep impossible?

“Reading an email,” said Robin.

“They think,” said Linda (and Robin knew “they” must be the new parents, whose thoughts and wishes were of all-consuming importance just now) “it was the sprouts. She’s been colicky all night. Jenny’s exhausted.”

“Annabel didn’t have sprouts,” said Robin.

“She gets it all through the breast milk,” explained Linda, with what felt to Robin like condescension for being excluded from the mysteries of motherhood.

Bearing two cups of tea for Stephen and Jenny, Linda left the room again. Relieved, Robin opened her notebook and jotted down a couple of thoughts that had occurred to her while reading “Possible leads,” then returned to Strike’s document to read his short list of “Probably irrelevant” items gleaned from Talbot’s notebook.

Paul Satchwell

After a few months, Talbot’s mental state clearly deteriorated, judging by his notes, which become progressively more detached from reality.

Toward the end of the notebook he goes back to the other two horned signs of the zodiac, Aries and Taurus, presumably because he’s still fixated on the devil. As stated above, Wilma comes in for a lot of unfounded suspicion, but he also goes to the trouble of calculating Satchwell’s complete birth horoscope, which means he must have got a birth time from him. Probably means nothing, but strange that he went back to Satchwell and spent this much time on his birth chart, which he didn’t do for any other suspect. Talbot highlights aspects of the chart that supposedly indicate aggression, dishonesty and neuroses. Talbot also keeps noting that various parts of Satchwell’s chart are “same as AC” without explanation.

Roy Phipps and Irene Hickson