Keeping with the personal angle, they went through Prior Silver’s files to see if they could find a collaborator in his robbery spree that could be a possible target, but there had been none. They even interviewed a few of Silver’s former cell-block mates up at Wakefield and Hatfield, the prisons where he had served time. The interviews yielded nothing useful. None of the inmates recalled Silver having any sort of altercation with an imprisoned thief that he might now have his sights set on. Silver had kept to himself, his nose buried in his little black Bible, steeping himself in an ideology that he apparently twisted to fuel his murderous rampage.

As London shut down in preparation for the holiest of nights, Deputy Commander Stebbins suggested everyone go home for the evening. It was a time to be with loved ones; by replenishing themselves they might return from the holiday with a fresh perspective and pick up something they had missed.

Rachel called Everett and told him to expect all three of them for dinner. When she asked what they could bring, all she heard was gratefulness in her uncle’s voice. “Just the three of you. It’s the best Christmas present I could ask for.”

Rachel said they would see him shortly and hung up. She looked across the desk at her father and John. Their expressions remained glum; if Marley’s ghost had stumbled in right then, he would have felt right at home.

Rachel and her father arrived at Everett’s and saw that the Oxford don had pulled out all the holiday stops. The house just off the Hamstead High Street was all a-twinkle with elegant strands of blinking white lights and had a hearty ivy and berry wreath affixed to the door.

Everett greeted them with warm hugs, took their coats, and ushered them into the library where John was already ensconced, two sips into an Old Fashioned. Her uncle provided them with companion cocktails after displaying the bottle of eighteen-year-old Macallan John had brought. Her father’s nod of approval indicated to Rachel that the detective had gone up in his estimation, and it sweetened the pot when he presented Grant a bottle of his very own.

“It’s too damned cold for a chocolate shake,” John said.

As they worked their drinks, John indicated the chess board and asked if that’s where Grant and Everett had first put together the Commandment connection.

Rachel’s uncle nodded. “The one and the same.”

“I can’t imagine where we’d be right now if you hadn’t gone and dusted that Bible off the shelf,” said Grant.

“I’d think by the time this maniac Silver had crossed the Atlantic and risen the count to four or five, you would have deduced the pattern,” Everett told them.