“You know,” said Robin thoughtfully, “I think I’ve seen ‘Blanc de blanc’ somewhere recently.”

“Yeah? Been drinking champagne?” asked Strike, who had sat down to make more notes.

“No, but… yeah, I suppose I must’ve seen it on a wine label, mustn’t I? Blanc de blancs… what does it mean? ‘White from whites?’”

“Yeah,” said Strike.

For nearly a minute, neither of them spoke, both examining the note. “You know, I hate to say this, Robin,” said Strike at last, “but I think the most interesting thing about this is that Flick had it. Looks like a to-do list. Can’t see anything here that proves wrongdoing or suggests grounds for blackmail or murder.”

“Mother, crossed out,” Robin repeated, as though determined to wring meaning out of the cryptic phrases. “Jimmy Knight’s mother died of asbestosis. He just told me so, at Flick’s party.”

Strike tapped his notepad lightly with the end of his pen, thinking, until Robin voiced the question that he was grappling with.

“We’re going to have to tell the police about this, aren’t we?”

“Yeah, we are,” sighed Strike, rubbing his eyes. “This proves she had access to Ebury Street. Unfortunately, that means we’re going to have to pull you out of the jewelry shop. Once the police search her bathroom, it won’t take her long to work out who must’ve tipped them off.”

“Bugger,” said Robin. “I really felt like I was getting somewhere with her.”

“Yeah,” Strike agreed. “This is the problem with having no official standing in an inquiry. I’d give a lot to have Flick in an interrogation room… This bloody case,” he said, yawning. “I’ve been going through the file all evening. This note’s like everything else: it raises more questions than it answers.”

“Hang on,” said Robin, and he heard sounds of movement, “sorry—Cormoran, I’m going to get off here, I can see a taxi rank—”

“OK. Great work tonight. I’ll call you tomorrow—later today, I mean.”

When she had hung up, Strike set his cigarette down in the ashtray, returned to his bedroom to pick up the scattered case notes off the floor, and took them back to the kitchen. Ignoring the freshly boiled kettle, he took a beer from the fridge, sat back down at the table with the file and, as an afterthought, opened the sash window beside him a few inches, to let some clean air into the room while he kept smoking.

The Military Police had trained him to organize interrogations and findings into three broad categories: people, places and things, and Strike had been applying this sound old principle to the Chiswell file before falling asleep on the bed. Now he spread the contents of the file out over the kitchen table and set to work again, while a cold night breeze laden with petrol fumes blew across the photographs and papers, so that their corners trembled.

“People,” Strike muttered.

He had written a list before he slept of the people who most interested him in connection with Chiswell’s death. Now he saw that he had unconsciously ranked the names according to their degree of involvement in the dead man’s blackmail. Jimmy Knight’s name topped the list, followed by Geraint Winn’s, and then by what Strike thought of as each man’s respective deputy, Flick Purdue and Aamir Mallik. Next came Kinvara, who knew that Chiswell was being blackmailed, and why; Della Winn, whose super-injunction had kept the blackmail out of the press, but whose precise degree of involvement in the affair was otherwise unknown to Strike, and then Raphael, who had by all accounts been ignorant both of what his father had done, and of the blackmail itself. At the bottom of the list was Billy Knight, whose only known connection with the blackmail was the bond of blood between himself and the primary blackmailer.

Why, Strike asked himself, had he ranked the names in this particular order? There was no proven link between Chiswell’s death and the blackmail, unless, of course, the threat of exposure of his unknown crime had indeed pushed Chiswell into killing himself.

It then occurred to Strike that a different hierarchy was revealed if he turned the list on its head. In this case Billy sat on top, a disinterested seeker, not of money or another man’s disgrace, but of truth and justice. In the reversed order, Raphael came in second, with his strange and, to Strike, implausible story of being sent to his stepmother on the morning of his father’s death, which Henry Drummond claimed grudgingly to have hidden some honorable motive as yet unknown. Della rose to third place, a widely admired woman of impeccable morality, whose true thoughts and feelings towards her blackmailing husband and to his victim remained inscrutable.

Read backwards, it seemed to Strike that each suspect’s relation to the dead man became cruder, more transactional, until the list terminated with Jimmy Knight and his angry demand for forty thousand pounds.

Strike continued to pore over the list of names as though he might suddenly see something emerging out of his dense, spiky handwriting, the way unfocused eyes may spot the 3D image hidden in a series of brightly colored dots. All that occurred to him, however, was the fact that there was an unusual number of pairs connected to Chiswell’s death: couples—Geraint and Della, Jimmy and Flick; pairs of full siblings—Izzy and Fizzy, Jimmy and Billy; the duo of blackmailing collaborators—Jimmy and Geraint; and the subsets of each blackmailer and his deputy—Flick and Aamir. There was even the quasi-parental pairing of Della and Aamir. This left two people who formed a pair in being isolated within the otherwise close-knit family: the widowed Kinvara and Raphael, the unsatisfactory, outsider son.

Strike tapped his pen unconsciously against the notebook, thinking. Pairs. The whole business had begun with a pair of crimes: Chiswell’s blackmail and Billy’s allegation of infanticide. He had been trying to find the connection between them from the start, unable to believe that they could be entirely separate cases, even if on the face of it their only link was in the blood tie between the Knight brothers.

Turning the page, he examined the notes he had headed “Places.” After a few minutes spent examining his own jottings concerning access to the house in Ebury Street, and the locations, in several cases unknown, of the suspects at the time of Chiswell’s death, he made a note to remind himself that he still hadn’t received from Izzy contact details for Tegan Butcher, the stable girl who could confirm that Kinvara had been at home in Woolstone while Chiswell was suffocating in a plastic bag in London.

He turned to the next page, headed “Things,” and now he set down his pen and spread Robin’s photographs out so that they formed a collage of the death scene. He scrutinized the flash of gold in the pocket of the dead man, and then the bent sword, half hidden in shadow in the corner of the room.

It seemed to Strike that the case he was investigating was littered with objects that had been found in surprising places: the sword in the corner, the lachesis pills on the floor, the wooden cross found in a tangle of nettles at the bottom of the dell, the canister of helium and the rubber tubing in a house where no child’s party had ever been held, but his tired mind could find neither answers nor patterns here.

Finally, Strike downed the rest of his beer, lobbed the empty can across the room into the kitchen bin, turned to a blank page in his notebook and began to write a to-do list for the Sunday of which two hours had already elapsed.