Billy heard a scraping sound in the dark, a sound from behind the ratty curtain that hung across the door of his bedroom.

"Hello?" he whispered.

Bedroom was an overstatement, actually. Billy slept in a concrete cell three floors below the ground, with just enough room for his bed and nothing else.

"Who's there?"

"Shut up!" whispered a raspy voice.

There were no windows anywhere. After the lights went out at 10pm each night, Billy was forced to exist in thick, uninterrupted darkness.

More scraping. The curtain started to move.

"Please don't hurt me."

"Ssshhhh!"

"I can't tell you anything. They told me not to talk to you. If I tell you anything they'll hurt me. They'll hurt me worse for talking to you than you'll hurt me for not talking to you. So please . . . please just leave me alone. Please?"

Billy was terrified of the dark. Each night just before lights-out, he made sure he was arranged just so: lying flat on his back, slightly propped up on two pillows, arms crossed over his chest. This was not a very comfortable position for sleeping, but he felt it was the best way to face the darkness.

As he felt the midnight visitor creeping closer to him, he tried to stay very, very still. He always imagined that if he could just stop moving, stop breathing, they might not know where to find him in the dark. But he couldn't do it. His body just wouldn't stop trembling.

He used to scream when the nightmares came. But he had learned that the guards didn't like that kind of trouble. So he just swallowed really hard when he felt rough hands touching his face, clamping down over his mouth.

"Billy, you have to be very, very quiet." The lips were pressed right up against his ear, tickling, making the smallest of whispers.

And Billy relaxed.

"I thought you were a nightmare, Cal!" he said with relief. But of course, all sound was muffled by Cal's thick hands.

"It's time to go, Billy. Did you pack your stuff?"

Billy nodded.

"OK. They've probably noticed me on the cameras by now, so we have to do this quick."

Billy nodded again.

"There's one thing, Billy, and I'm really sorry about this. Last time we got out . . . well, they put something inside you. A little electronic thing that tells them where you are all the time. They'll find us unless . . . unless I take it out."

Billy didn't understand. He stared blankly into the darkness.

"It's the only way, buddy boy. I'm real sorry. Just . . . try not to yell. Bite my hand if you have to."

And then the pain started . . . the stabbing. Billy tried very hard not to scream. But he couldn't help himself.