In the hallway, the end door to the kitchen was closed, as was the door to his study on the right. To the left, the library door stood open, and lights were on in that room.

On the floor were approximately twenty books in three stacks. Grady had not left them there.

Curious, he knelt to examine the volumes. They were a mix of nonfiction and fiction in various genres. At first he could see no connection between them-and then he realized that all of the dust jackets of all the chosen books had exceptionally colorful spines: red, yellow, hot pink, orange…

Because his books were arranged alphabetically, Grady knew that the selection had been taken from both low and high shelves and from half a dozen points around the room. Cold reason suggested he could dismiss from consideration the possibility that Merlin had learned to climb.

The suspicion arose that he had been prudent to go barefoot and not to announce himself in any fashion since coming downstairs. In the hallway, he listened attentively and heard furtive noises behind the end door.

Stepping into the kitchen, he found the wolfhound sitting at the open pantry. At first there was no sign of Puzzle and Riddle, but then from the pantry appeared a white furry arm ending in a coal-black hand that offered a Ritz cracker slathered with peanut butter.

For a dog his size, Merlin routinely accepted any treat with a gentleness that was surprising, taking it with soft lips and quick tongue, never with a rudeness of teeth, finessing it from fingers instead of snatching. He accepted the Ritz cracker with his usual good manners.

As the dog munched the cracker and lavishly licked his chops, he turned his head to Grady. His expression suggested that henceforth his dad could sleep late every morning while his new best friends whipped up breakfast.

When Grady peered into the pantry, he discovered Puzzle and Riddle sitting on the floor as they had sat on the sofa the previous evening, not like dogs or even like prairie dogs, but as if they were human children. Their legs were straight in front of them.

Between her thighs, Puzzle held an open family-size jar of Skippy peanut butter. Riddle took a cracker from the Ritz box and passed it to her.

Reaching into the jar with her right hand, Puzzle scooped out a gob of Skippy’s finest. She smeared it on the cracker that she held in her left hand.

She returned the cracker to Riddle. He fed it to himself with his left hand while he plucked another cracker from the box with his right.

The fur around their black lips remained remarkably free of peanut butter; however, golden cracker crumbs littered their white coats.

“I’m surprised you’re not having some grape jelly with that,” Grady said.

The two astonishments looked up at him, smacking their lips with satisfaction.

“Sorry if you prefer chunky peanut butter. I’m afraid I only have smooth.”

In unison, the pair cocked their heads, regarding him as though he was the most peculiar creature they had ever encountered.

Grady stepped past Merlin and into the big pantry. He bent down to take the cracker box from Riddle and the jar of Skippy from Puzzle.

Although they didn’t attempt to hold fast to their treasures, they made soft sounds of dismay, a sort of warbling-mewling, and Riddle put a hand on Puzzle’s shoulder as if to comfort her.

Grady said, “If you’ve really moved in, like Cammy thinks, I guess I’ll have to monkeyproof the house.”

He snared the lid of the Skippy jar and took everything into the kitchen. He put the lid on the peanut butter, closed the box of crackers, opened a lower cabinet door, and dropped both items into a small trash can.

When he turned around, the two were sitting in the middle of the floor, intently watching him. Riddle continued to smack his lips, and Puzzle had three fingers in her mouth at once, assiduously cleaning away every trace of Skippy. They appeared to have brushed the cracker crumbs from their chest fur.

In the open pantry, Merlin sniffed the floor with the enthusiasm of a bloodhound, licking up the debris.

“The cracker box is still nearly full,” Grady said, “so I assume you only had a few. You still get kibble. But I’ll have to look into fitting out the pantry with a titanium-steel vault door with a laser scanner that reads my palm print.”

He rinsed the three drinking bowls and filled them with fresh cold water. Then he dished up three servings of kibble and placed them side by side on the floor.

As before, Puzzle and Riddle followed Merlin’s lead, sitting in front of their bowls, waiting for the word from Grady-“Okay”-that formally announced Breakfast is served.

While the three pals ate as if they had never in their lives encountered peanut butter, Grady put a filter in the coffeemaker. From a can, he spooned enough Jamaican blend to make ten cups.

He heard a noise at the back door. Turning, he saw Merlin and Puzzle waiting while Riddle, standing on his hind legs, worked the knob with both hands.

Evidently, Riddle had already disengaged the deadbolt with the thumbturn. Now the latch bolt released and the door eased open.

Riddle dropped onto all fours and pushed the door out of his way. He scampered onto the porch, followed by Puzzle and Merlin.

Stepping to the window, Grady watched as the quick pair led the wolfhound across the yard to the taller meadow grass. Only the night before, Merlin had shown them that the meadow, rather than the lawn, was an appropriate toilet.

Grady went to the open back door and worked the thumbturn a few times, extending and retracting the deadbolt. The lock was simple to operate. No degree in engineering was required.

He couldn’t remember for sure, but they probably had seen him use the thumbturn.

At the coffeemaker again, he poured ten cups of water into the reservoir, put the glass carafe on the warming plate, and twisted the brew switch.

Returning to the window, he saw the three pals chasing around the yard: bounding exuberantly this way and that, tumbling, rolling, up and running again.

“Maybe if you watch me do it at dinner tonight,” Grady murmured, “you can have coffee ready for me in the morning.”

Lamar Woolsey took an early-bird flight out of Las Vegas and landed in Denver in time for a late breakfast, which he did not get to order, let alone eat, because two men were waiting for him when he came off the enclosed jet bridge into the terminal. They were in the area from which, since September 2001, everyone except airport personnel and ticketed passengers was excluded.

The moment that he spotted them, Lamar knew they were waiting for him. They had a look with which he was familiar: fully ready but pretending weariness, vigilant but feigning indifference. One of them had a hands-off cell phone, shaped like an ocarina but hardly bigger than a peach pit, hooked over his right ear.

Out of courtesy, so they would feel that their plainclothes disguise was effective, Lamar looked away from them and continued walking until the one without the cell phone called his name. Then he halted, turned to them as they approached, and said, “Ah, you must be with the conference.”

The one with the cell phone said, “No, sir,” and with a gesture encouraged Lamar to step out of the flow of disembarking passengers.

Neither of them spoke the name of his agency, but when they flopped open their ID wallets, Lamar wasn’t surprised to see that they were with the Department of Homeland Security: Derek Booker, Vincent Palumbo.

“I assume I won’t be able to keep my commitment to speak at the conference.”

Encouraging Lamar to walk with them, Palumbo said, “No, sir, you won’t. The organizers have already been told you’ve got to withdraw from the program due to a sudden illness.”

“What illness might that be?” Lamar asked.