Uzi, N, V, J, and Doll were wandering Copper-9. Uzi, getting bored, decides to mess with her Solver again, and, as you know by now, winds up throwing everyone into another universe. Except this time it just knocks everyone out. When they awake, they find themselves in a huge chamber with a few fire plumes, and a ruined, blazing Anti-Mass Spectrometer in the center. Some text flashes across their HUD...

CHAPTER 3: UNFORSEEN CONSEQUENCES

The gang looks around, confused. They then realize they all are in H.E.V. suits. Uzi: ... what is this suit, even? N: Woah, cool! is obviously interested in the HEV suit Mk. IV V: Weird. J: Soooo, nobody is going to question why we're in a place called... she squints her eyes at a logo on the wall ... Black Mesa...? Doll: Хм, странно. (Huh, weird.)