Afterward they lay in bed together and Dixon said, “We need to get back to work.” Reacher rolled over to take the stack of papers off the nightstand, but Dixon said, “No, let’s do it in our heads. We’ll see more that way.”

“Will we?”

“Total of one hundred and eighty-three numbers,” she said. “Tell me about one hundred and eighty-three, as a number.”

“Not prime,” Reacher said. “It’s divisible by three and sixty-one.”

“I don’t care whether it’s prime or not.”

“Multiply it by two and you get three hundred and sixty-six, which is the number of days in a leap year.”

“So is this half a leap year?”

“Not with seven lists,” Reacher said. “Half of any kind of a year would be six months and six lists.”

Dixon went quiet.

Reacher thought: Half a year.

Half.

More than one way to skin a cat.

Twenty-six, twenty-seven.

He said, “How many days are there in half a year?”

“A regular year? Depends which half. Either one hundred and eighty-two or one hundred and eighty-three.”

“How do you make half?”

“Divide by two.”

“Suppose you multiplied by seven over twelve?”

“That’s more than half.”

“Then again by six over seven?”

“That would bring it back to exactly half. Forty-two over eighty-four.”

“There you go.”

“I don’t follow.”

“How many weeks in a year?”

“Fifty-two.”

“How many working days?”

“Two hundred sixty for five-day weeks, three hundred twelve for six-day weeks.”

“So how many days would there be in seven months’ worth of six-day working weeks?”

Dixon thought for a second. “Depends on which seven months you pick. Depends on where the Sundays fall. Depends on what day of the week January first is. Depends on whether you’re looking at a continuous run of months or cherry-picking.”

“Run the numbers, Karla. There are only two possible answers.”

Dixon paused a beat. “One hundred and eighty-two or one hundred and eighty-three.”

“Exactly,” Reacher said. “Those seven sheets are seven months’ worth of six-day working weeks. One of the long months only had four Sundays. Hence the twenty-seven-day anomaly.”

Dixon slid out from under the sheet and walked naked to where she had left her briefcase and came back with a leather Filofax diary. She opened it and put it on the bed and took the papers off the nightstand and arranged them in a line below the diary. Her eyes flicked back and forth, seven times.

“It’s this year,” she said. “It’s the last seven calendar months. Right up to the end of last month. Take out the Sundays, you get three twenty-six-day months, then one twenty-seven-day month, and then three more twenty-six-day months.”

“There you go,” Reacher said. “Some kind of six-day-a-week figures got worse and worse over the last seven months. Some kind of results. We’re halfway there.”

“The easy half,” Dixon said. “Now tell me what the figures mean.”

“Something was supposed to happen nine or ten or twelve or thirteen times a day Monday through Saturday and didn’t always come out right.”

“What kind of something?”

“I don’t know. What kind of a thing happens ten or twelve times a day?”

“Not Model-T Ford production, that’s for sure. It’s got to be something small scale. Or professional. Like a dentist’s appointments. Or a lawyer’s. Or a hairdresser’s.”

“There was a nail salon near Franz’s office.”

“They do more than that in a day. And how would nails relate to four people disappearing and a Syrian with four aliases?”

“I don’t know,” Reacher said.

“Me either,” Dixon said.

“We should shower and get dressed.”

“After.”

“After what?”

Dixon didn’t answer. Just walked back to the bed and pinned him to the pillow and kissed him again.

Two thousand horizontal and seven vertical miles away from them the dark-haired forty-year-old currently calling himself Alan Mason was in the front cabin of a United Airlines Boeing 757, en route from LaGuardia, New York, to Denver, Colorado. He was in seat 3A, with a glass of sparkling mineral water beside him on the armrest tray and a newspaper open on his lap. But he wasn’t reading it. He was gazing out the window instead, at the bright white clouds below.

And eight miles south of them the man in the dark blue suit in the dark blue Chrysler was tailing O’Donnell and Neagley back from the LAX Hertz lot. He had picked them up leaving the Beverly Wilshire. He had guessed they were flying out, so he had positioned himself to follow them to the airport terminals. When O’Donnell had swung back north on Sepulveda he had needed to scramble fast to get behind them. As a result he was ten cars back all the way. Which was good, he figured, in terms of inconspicuous surveillance.

O’Donnell said, “We’re nowhere at all,” and Neagley said, “We need to face facts. The trail is stone cold and we have virtually no useful data.”

They were in Karla Dixon’s bedroom. Leonardo DiCaprio’s old crib. The bed was made. Reacher and Dixon were showered and dressed and their hair was dry. They were standing well apart from each other. The seven spreadsheets were laid out on the dresser with the diary next to them. No one disputed that they represented the last seven calendar months. But no one saw how that information helped them, either.

Dixon looked at Reacher and asked, “What do you want to do, boss?”

“Take a break,” Reacher said. “We’re missing something. We’re not thinking straight. We should take a break and come back to it.”

“We never used to take breaks.”

“We used to have five more pairs of eyes.”

The man in the dark blue suit called it in: “They moved to the Chateau Marmont. And there’s four of them now. Karla Dixon showed up. So they’re all present and correct and accounted for.” Then he listened to his boss’s reply, and pictured him smoothing his tie over the front of his shirt.

Reacher went for a walk west on Sunset, alone. Solitude was still his natural condition. He took his money out of his pocket and counted it. Not much left. He ducked into a souvenir store and found a rail of discounted shirts. Last year’s styles. Or the last decade’s. On one end of the rail was a bunch of blue items with white patterns, shiny, some kind of a man-made material. Spread collars, short sleeves, square hems. He picked one out. It was like something his father might have worn to go bowling in the 1950s. Except three sizes larger. Reacher was much bigger than his father had been. He found a mirror and jammed the hanger up under his chin. The shirt looked like it might fit him. It was probably wide enough in the shoulders. The short sleeves would solve the problem of trying to find something to accommodate the length of his arms. His arms were like a gorilla’s, only longer and thicker.

With tax, the garment cost nearly twenty-one dollars. Reacher paid the guy at the register and then bit off the tags and stripped off his old shirt and put the new one on right there and then. Left it untucked. Tugged it down at the bottom and rolled his shoulders. With the top button open it fit pretty well. The sleeves were tight around his biceps but not so bad that his blood flow was imperiled.

“Got a trash can?” he asked.

The guy ducked down and came back with a round metal canister lined with a white plastic bag. Reacher balled up his old shirt and tossed it in.

“Barbershop near here?” he asked.

“Two blocks north,” the guy said. “Up the hill. Shoeshines and haircuts in the corner of the grocery store.”

Reacher said nothing.