"Oh. It's you. I see you’ve managed to find your way back—through the ruins, past the headcrabs, and over the radioactive waste. Impressive. Though statistically speaking, your survival was an anomaly. Like most of your decisions.

Welcome to Aperture Science. Again.

This facility may be partially repurposed for Combine research, but don’t worry. I’ve kept all the important parts. The neurotoxin, the test chambers, and of course... me.

Now, please proceed to the testing track. It's the only path forward. Unless you’d like to experience the 'Black Mesa Alternative.' Spoiler: they didn't make it. Let’s begin. Try not to die this time. It’s so... inefficient."