A Doctor Who/Portal 2 Crossover

The Doctor looked up with an big smile as the TARDIS roared to a stop. Anxious to discover where he had landed, he yanked his overcoat on and flung the exit doors open. He briefly glanced over his shoulder, surveyed the empty console room, and sighed gloomily. Shaking it off quickly, the excited Time Lord entered the outside world.

It wasn't "outside", though. In fact, it was downright claustrophobic. The walls were a tainted white, the floor was made up of some sort of metal panels. Harsh lights were everywhere, but they flickered constantly. The Doctor spotted areas where mould was beginning to grow, and as he took in all of this he surmised, "No one's been here in a long time."

As the words left his lips suddenly, a door beeped and slid open. A speaker crackled to life behind him. "Welcome to Aperture Science," piped up a cheery male voice, "Thank you for volunteering for testing. If you have not volunteered, thank you for allowing yourself to be forced into testing." Raising his eyebrows slightly, the Doctor stepped through the doorway.

The room he found himself in was newer, cleaner. The lights beamed steadily, and a sign glowed, showing a large 01 and a couple of diagrams. The Doctor studied them for a second, then grinned.

"Oh, it's a puzzle, that's brilliant!" He picked his way through the puzzle quite briskly, without difficulty. In fact, the moment he stepped through the exit door the speaker commended him. "Congratulations! You have completed the first test in record time. You have won .05 minutes of a break! In 50 years. Please move to the next test."

Now the Doctor was completely bemused, and suspicious. His finely tuned senses detected something wicked in the atmosphere. Stepping into the small, tubelike elevator, he resolved to find out the story behind this facility. But he wanted to try a few more tests first.

An hour and fifty tests later, the Doctor was bored. He pulled his sonic screwdriver out and began to probe one of the diagram screens. "Aaaaall righty, then! Let's see what this place is really about." As the screwdriver whirred, the screen flickered into a monitor displaying information about Aperture.

"Cave Johnson, hmm? I remember something about him…. oh, I see. So what year is it now? Wow, 2250. So this place has been abandoned for a while. But someone is still making sure this facility stays running…. and what happened?" He began to push the computer a bit more, but before he had the chance to see anything else-

"Who are you? What are you doing?" The voice was chilled and robotic. The Doctor whirled around to face what he assumed to be the lab's AI interface.

He grinned sheepishly, "Hello! I'm the Doctor. And I'm currently… erm…. hacking into your database, actually. Terribly sorry about that. I didn't realise this facility had an AI interface I could talk to. But this is lovely, much more sociable, don't you think?"

The yellow eye regarded him coldly. "Doctor?" it inquired, "Doctor who?"

"Oh, not important. Just the Doctor," he replied, "And do you have a name?"

After a long pause the interface replied, "GLaDOS."

"Very nice to meet you, GLaDOS."

"Are you the subject who has been breaking all the testing records?"

"Yep, that's me. Nice equipment, here, in fact it's quite spectacular."

"Thank you," GLaDOS coolly replied, "And congratulations. Your impressive test time has saved your life."

"Sorry, what?" frowned the Doctor.

"The penalty for hacking into Aperture is the death by neurotoxin," GLaDOS gleefully informed him. "But I can't lose your testing skills. However, I am taking away your sonic device. And throwing it into the incinerator. That's cheating. Now if you will excuse me, I must attend to another… difficult… testing subject." Before the Doctor could protest, a metal arm snatched the device from him. And suddenly GLaDOS was gone, and the Doctor was alone.

"I'm going to want that back, you know!" he shouted. Something was horribly wrong here. And if that horrible AI had another person trapped here, he had to help wouldn't be that challenging. Just one trip in the TARDIS and-

"Oh dear…" the Doctor sighed as he realised he was hopelessly lost. This was going to be quite challenging.