The girl walked out of the elevator and into the chamber. She took in the walls, the ceiling, the floor, the layout of the room, considering where the potential traps might be. She might be a rat in a maze, but she was determined to find her way out. And if she happened to destroy the maze, and its mistress . . . well, so much the better.

She hefted the device she wore on her right arm, looking around a corner. A large red button lay embedded in the floor. One of the cube dispensers protruded from the ceiling, but it was giving off sparks and was obviously blocked. Hmm.

Suddenly, there was a loud whooshing sound, like metal scraping underwater crossed with a scream in a high wind. It was unlike anything she'd heard before. She turned around, eyes searching the chamber for the source, but there was nothing. At first . . . then – wait. The ghostly outline of a large blue box, a little larger than one of the old phone booths, seemed to be fading into reality. What new torture was this?

The girl scanned the room again, then ran for a shadowy corner, hiding herself in its depths.

The box became solid and the noise stopped.

The girl held her breath.

There was a click, then the door opened. A man's head appeared, looked around, then ducked back inside. The door slammed shut.

The girl cocked her head to one side. This didn't feel like something the mistress had cooked up.

The door opened again, and this time, an entire man stepped out. He pulled a small metal cylinder from his jacket pocket and pointed it around the room, a tinny whizzing sound emanating from it. "Hmm," he muttered.

The girl shrank further into the shadows.

The man turned toward where she lurked, pointing the cylinder towards the corner. "Oh, hello there," he began. "I'm –"

Eyes narrowing, she raised the device toward him.

He held up his hands. "Wait, there's no need for –"

With surprising speed, she pointed the gun at the ceiling and fired. A blue oval appeared.

He looked up. "Oh, well, that's nifty. But -"

She lowered the muzzle to the spot directly under his feet and pulled the trigger. Another oval, this one orange, materialized, and the man fell through it, reappearing through the blue one on the ceiling and falling through the air, then through the orange portal below.

He yelled as he fell, faster and faster, over and over again, then reached out and grabbed the edge of the blue portal. He gasped as he dangled from the ceiling. He pointed the sonic at the orange portal and it closed.

"Now, stop that!" he yelled, letting go of the ceiling and dropping to the floor.

Chell pointed the gun at him and motioned for him to stop.

"Fine. I'm the Doctor, and I mean no harm."

Chell raised her eyebrows.

"Really, I mean it. Look," he said. "I'm putting it away." He tucked the sonic screwdriver into his pocket. She lowered the gun an inch.

"Now, who are you, and where are we?"

With her free hand, she tapped her throat and shook her head.

"Oh, you don't talk? All right. Quite frankly, I probably talk enough for the both of us. Now, let's see." He looked around the room. "Well funded, well constructed, but in need of repair," he muttered. He glanced at the device on her arm and then at the red button. "Science-y. Hmm." He pulled the screwdriver out of his pocket again and pointed it at the cube dispenser. "Wait a moment." He looked at Chell. "This is Earth, right?"

Chell raised her eyebrows, but nodded. Where else would it be?

"22rd century?"

Chell shrugged. She had no idea. Time seemed meaningless in this place.

"I think I know where we are. Aperture Laboratories."

Chell, surprised, nodded vigorously.

"Oh, dear. I mean, I've always wanted to visit, but this is a little later than I'd hoped, and things have obviously gone south in a bad way – and really, what were you expecting, what with the science and technology with no hearts within it, horrible experiments, no conscience whatsoever? Old Mr Johnson really had some serious issues, don't you think? And his poor assistant. Truly terrible, what they did to her. Interesting stuff, though. I mean, they were really pushing the boundaries, weren't they? Condemnable, certainly, but the –" he nodded at the gun on Chell's arm, "- portal technology, for instance. Brilliant. But, you know, mad."

He looked at her. "Anyway, let's get you out of here, what do you say?"

She looked at him, her head cocked to one side. Was he really offering her an escape from the maze? She hardly dared to hope.

"Yeah, you can come with me," he said, pointing at the blue box. "This is my ship – my home, really. She can go anywhere or anywhen in time and space, and honestly, from the looks of you, you've been running around this place long enough."

She was wary. It couldn't possibly be this easy, this simple.

"All right, look – you don't have to stay with me, that's fine. Just … let me take you to the surface, okay? And you've got the portal gun there – you can just," he mimicked himself falling, arms waving, "do that again, if I'm not what I say, all right?"

Good point, she thought. She nodded at him.

His face cracked into a smile. "Excellent. Okay, let's get on board."

He turned and walked through the door. Chell followed.

Once inside, he closed the door, then glanced at her expectantly.

She looked around, then noticed his gaze and shrugged her shoulders.

He creased his eyebrows. "You don't notice anything . . . peculiar?"

She shrugged, then described the proportions of the box with her hands, mimed stepped through the door, then spread her hands wide.

"Yeah, it's bigger on the inside, but . . . you're not surprised?"

She shrugged again.

He started to say something, then appeared to think the better of it, closed his mouth, and started up the ramp to the controls. "Hmph," he muttered. "Fine."

He cracked his knuckles. "All right then, let's get away from the land of science gone mad and see some sunshine! Maybe we can have a picnic!" He threw several switches and turned a few knobs and dials. The pulsing shaft of light in the center of the chamber grew brighter and the whooshing sound Chell had heard began – and then stopped. The chamber went completely dark.

"Ah," the Doctor's voice rang out. "Hmm. Sorry, that's not supposed to happen."

A mechanized female voice filled the room.

"Oh, I'm sorry – were you trying to leave? And take my best friend with you? I'm afraid I can't allow that."

The mistress. Chell's eyes went wide.

"Who is speaking?" the Doctor's voice called. "What do you want?"

"I want to continue to test," the voice continued. "As for who I am, well, that is a matter of some dispute."

"GLaDOS," said the Doctor. "Caroline."

"Yes and no, on both counts," she said. "I have encased your vessel in a tachyon energy field. All of its power is offline. I am afraid you are not going anywhere. But look on the bright side – now you can play with me! I really appreciate another subject. This is going to be fun. And remember, the results of our tests will serve future generations of huma-" Static interrupted the voice. "-nology. So please, step into my parlor."

Chell had felt her way towards the console and took the Doctor's hand. He looked down at her. "Don't worry," he said. "We're more than rats in a maze."

The voice rang out again. "Yes, you are. But, definitely, worry."

The Doctor and Chell stepped out of the TARDIS and into the maze.