A Fight on All Fronts

A former H.E.C.U. Marine, Adrian Shepherd, sent to a unknown place, brought back to kick some ass, but the threat is much worse than aliens from Zen... Now with a team consisting of Ghost, Cross, and Nightmare, he's going to fight someone like Nightmare, a brother, lost to darkness.

(SPOILERS TO HALF-LIFE, AND HALF-LIFE OPPOSING FORCE! READ OR PLAY THE GAME BEFORE READING!)