„Hey, at least the box has been teleported," said Doug, took the Prelude box and read the text on the back.

Portal: Prelude, as its name states it, is an unofficial prequel to the game Portal. Its story revolves around pre-GLaDOS epoch, even before she was plugged in. At this time, test subjects were monitored by real Aperture Science employees, whose work was tedious, lengthy and repetitive. This is why they decided to build a great artificial intelligence that could both replace them in these difficult tasks, and also take responsibility for many other tasks within the complex and compete with Black Mesa's superiority. All employees of the Aperture Science complex are now eagerly awaiting GLaDOS. Maybe even a little too eagerly, as the upcoming events will tell.

"Okay, so what I get is that this employee is imitating the personality of GLaDOS to help build the stupidest artificial intelligence personality of all time. No shit why she's being waited for a little too eagerly."

The Aperture Scientist said: "GLaDOS? I never heard of that name."

Chell knew the answer. "He meant ASCAIS. You see, we're from the future that is called Portal 2 where GLa- ASCAIS and another AI have conquered the Aperture Labs and we've got to stop them and trigger the Aperture Science Golden Age."

"Well, you're still not allowed to go until I receive the Portal Device."

Chell thought: "There will be nothing from arguing." She gave the Scientist her Portal Device.

A strange voice that could be compared to HEV Suit's voice said: "Programmed responses activated." Then the scientist came on: "Thanks! Now please, come in. Most of us are already back from the party. Feel free to visit."

Chell and Doug came through the newly opened door and saw what looked like the main hallway of the Aperture Science Laboratories (yes, this name is outdated too). One sign of the hallway was called "Aperture Science G-Labs Sector." Then another programmed voice said: "Hello Abby. They're waiting for you, in the employees' lounge. It's the next door on your left."

"Nevermind that. We're going to GLaDOS. And since the closest name to "GLaDOS" that I see is "G-Labs", we're going there.

They went up to the second level and through the closed door. But since neither people nor boxes can go through the closed doors, they took another door. They then turned right, opened the door and saw the party down there.

"Let's go to the party." They jumped down and the programmed response once again was played.

"Congratulations Abby! You made it! Look guys! Our very first test subject to reach the end of the test alive!"

"What test? You mean Blue Portals? I actually bypassed Chambers 03 to 09 and glitched Chamber 10," said Chell. "And stop referring to "Abby"."

Programmed responses deactivated.

"So then who you really are?"

"My name is Chell Johnson, and with me came Doug Rattmann."

"Doug Rattmann? You mean the one who made the Aperture Image Format to simulate all the screens?"

"Yes, that same one."

"But he's actually there." Another scientist that was younger Doug Rattmann stood up and started talking with Doug, while Chell continued.

"I'm from the future that is called Portal 2 and I need to go back to it to trigger the Aperture Science Golden Age."

"I can't help you unless ASCAIS, which they're coincidentally going to plug in a few minutes, invents something. So, here's the deal. We offer you to witness this event, live, with us. Go take a tour in the complex, while we work on the very last details. I'll send you someone to show you the way, in a few minutes. And when she's plugged in, you'll come to her room and make a deal with her."

"Okay. Deal accepted."

Then Chell, ignoring Doug, went back to the corridor where she had turned right, except this time, she walked straight into the observation room which showed a chamber numbered "06". "Hey, I know that chamber from the first Portal."

Nostalgically, she broke the window with the knife that she still had from Blue Portals 02 and took the Portal Device from there. It was blue portal-only, but after a weird fling that Chell executed, she managed to go back – with the Device.

Just as she went back to explore the so-called "employees' lounge", she crossed over another Aperture Scientist.

Programmed responses activated.

"Hello! Mike sent me to show you the way. Follow me, please," said the scientist (which looked identical to all other scientists, with white shirts and black trousers).

A door to G-Labs Sector opened, and Chell and the scientist went through. A corridor with a glass wall on the left was shown to Chell.

"On your left, you can see one of our several laboratories. In this one, we're creating modules for the artificial intelligence. For the moment, they're working on a morality processor. Something like that... Yesterday, I heard someone saying that the module was not yet ready for the official launch. I bet they're going to plug ASCAIS without it. Anyway... they can do whatever they want; it's not really my problem."

The corridor came to a weird end when only the door to the right was available.

"OK, here we are. You open this door. Go down one level. Open another door. Turn left. Take the elevator. Open another door. Leave the room. Go straight ahead, and hum... You turn right and it should be there. Good luck and have a nice day!"

Chell did everything as described, and another Aperture Scientist came to help Chell.

Programmed responses deactivated.

"Ah, there you are, Chell! Follow me, you are allowed to enter ASCAIS' room directly."

Chell took the path that she will use yet again twenty-three years later and came into what she knew was GLaDOS' room.

The room was full of Aperture Scientists that kept talking shit about developing the AI.

"Get ready guys! Here comes the last module."

"OK, come over here."

"Move up, move up…"

"OK, stop!"

"Move up, move up..."

"All right, got it."

"Put it behind, there must be a plug somewhere."

"This one?"

"No, this one is for the morality module. It's the other one, just above."

"OK, I see."

"All right, the module is connected."

"Hey, you, up there! We are ready. Switch the system on."

Someone at the observation room Chell hadn't seen before did something, and GLaDOS was turned on.

Everything happened in a split second. All the Aperture Scientists but not Chell were caught and burned down and what looked like a test subject was forced to jumped down. Then GLaDOS did a series of attacks on that another test subject which even if hit Chell, she (and the other test subject too) avoided, and it was shut down.

Abby! Abby! It's Mike!

"I heard this poem already back in 2107," said Chell.

Goddammit! Peter and Erik are dead! Everyone is dead here! I switched off the whole system, there was nothing else to do! I don't have much time to talk, the auxiliary generator will start in a few minutes. Listen, ASCAIS can't be stopped, there's pretty much nothing to do. There's only one thing you can try. Reach the laboratory, and bring the morality module here. But I don't think she will let you do anything without trying to stop you. First, try to find another portalgun and... and... what the hell is that?

Some weird sounds were heard behind.

Oh shi-

The scientist was killed.

"And on the topic of that "another portalgun," I have it here," said Chell looking at what she recognized as Abby.