The heavy doors flew open, and in came an angry Chell, followed by a timid Wheatley. He stayed by the door while Chell marched up to GLaDOS, who didn't seem all that phased by the test subject's loud and unexpected entrance.

"Oh, welcome back. Did you like my present? It took me a while to perfect the formula."

Chell crossed her arms and glared at the AI.

"What? Don't look at me like that. You only have yourself to blame for falling right into that blatantly obvious trap. So what if I may or may not have slipped something into the cake? Again, you're the one that fell for it."

"Uh, if I may- lemme just say something here-" Wheatley started.

"Quiet moron. This doesn't concern you." GLaDOS snapped.

She looked back to Chell, who was still waiting for something from GLaDOS.

"Look, if you want an apology you're not gonna get one. However, I guess we're even now."

Chell looked a bit confused as the AI continued.

"I quite enjoyed putting you back through old memories. Maybe I found it even more entertaining than having you run through the testing tracks. So, I'm willing to make a deal with you."

GLaDOS lowered herself to the ground and held out a hand to Chell.

"I get to perform more tests with you and the moron. You stop trying to kill me. If you succeed in holding your end of the deal, I don't kill you, and I might even give you a real cake this time."

That didn't sound like much of an offer to Chell. She pointed back at her friend in the doorway. What about Wheatley? What was in it for him?

"Oh, and the moron? What could he possibly want? And more importantly, why do you care?"

Chell stood her ground to make it look like she knew exactly what he wanted, when she really didn't. This whole time it wasn't even a thing she thought about. What did he want out of this? Why was he even still by her side?

"Uh, maybe I don't want to look like a human anymore. Anybody thought about that?" Wheatley called from behind.

GLaDOS thought for a minute.

"Fine. I'll fix that. But only if you keep your word. Keep in mind that I rarely ever make offers to anyone, test subject or non, so it would be quite stupid of you to turn it down. Do we have a deal?"

Chell marched up to GLaDOS, pondered, grasped her hand firmly, and nodded. GLaDOS smiled.

"Perfect, now let's get to business."

A portal gun dropped from the ceiling into Chell's arms. It felt oddly comfortable to be holding one of these again. On a wall off to the side, another door appeared.

"This first test involves redirection cubes. You remember those, right? Off you go. We have a lot of work to do."

GLaDOS really didn't waste any time. She must've been waiting for this for quite a while. Chell sighed and marched toward the door, followed closely by Wheatley. Alright, Chell thought. Let's get it over with.