Thomas Reed's supervisor, Agent Kowalski, called him into a windowless conference room at 10 AM on a Monday in October 1996. "Voss is missing," Kowalski said. "The Russians think you helped him disappear. They're not happy."

Thomas knew what this meant. The Russians had reach, even in America. If they thought Thomas betrayed them -- or betrayed Voss -- they would make him pay. Kowalski said: "Find Voss. Before someone decides you're the problem."

Thomas retraced Elias's last known movements. He visited the apartment Elias shared in Dorchester. It had been ransacked -- drawers pulled out, mattress slashed, a single photograph on the floor: Thomas and Elias at a baseball game, smiling. Thomas called Elias's mother. She said: "He called me last week. He said someone was watching him. He said the FBI was watching him."

Thomas hung up. He sat in his car and stared at the apartment building across the street from his own. He had noticed a car parked there for three days. Same car. Same driver. Or maybe the same person. He couldn't tell.

He went home. He locked the door. He checked the windows. In the corner of his living room, in the shadow behind his armchair, he saw something he didn't notice before: a small white object on the floor. He picked it up. It was a listening device.

***

Thomas removed all the devices over the course of three nights. There were seven in total -- in his apartment, in his car, in his office drawer. Someone had been watching him for weeks. He called Kowalski.

"It's inside the Bureau," he said. "Someone is feeding information to the Russians, and they're using me to find Voss because they want Voss dead and they don't want to do it themselves."

Kowalski was quiet. "What do you need?"

Thomas said: "I need to find Voss. Before they use me to do something I can't take back."

Thomas found Elias. Not in a hiding place or a safe house, but in the apartment directly below his own. Elias had been living there for six weeks, moving through the floorboards and ceiling, watching Thomas sleep, watch Thomas eat, watch Thomas sit alone in his dark apartment and stare at the wall.

"I didn't run," Elias said. "I couldn't. They were watching me everywhere. But I thought -- if I was here, below you, they wouldn't suspect. They'd think I was gone."

Thomas stared at him. His friend had been living in his walls. "Why didn't you tell me?"

Elias said: "Because I needed to know if I could trust you. And I know now."

Thomas didn't ask what he knew.

***

Thomas turned in his badge. He moved to a different city. He never spoke of Elias again.

But sometimes, in hotels, in rooms with thin walls, he lies in bed and listens to the sounds of the people next door -- or the people below, or the people above -- and he wonders if someone is always listening, always watching, always waiting.

He closes his eyes. He tells himself it is nothing. He tells himself every night. He is not sure he believes it.

The hotel room is on the fourth floor. The walls are thin. He can hear the couple next door arguing. He can hear the television in the room across the hall. He can hear the elevator ding. He can hear his own breathing.

He closes his eyes. He tells himself it is nothing. He tells himself every night.

He is not sure he believes it.

--- OTMES CODE APPENDED BELOW