A team of scientists have tampered in a realm of space that was to remain untouched. Guarded by a squadron of mercenaries, they find themselves in the middle of a galactic war between aliens and a species known as 'Predators.'
A first-person shooter featuring three separate story lines for each of the factions; Aliens, Colonial Marines, and Predators. Unlike later titles the three campaigns are unrelated and independent of each other.
Waking up unexpectedly from hypersleep, Lisbeth and the rest of the crew must figure out why the spaceship they are on, the Legato, has been diverted to intercept the USS Sulaco leaving LV-426's orbit.