In case you don't already know, or haven't already figured it out, Aliens: Colonial Marines is a direct sequel to the classic sci-fi/horror/mother-of-all-first-person-shooters film, Aliens. In Aliens: Colonial Marines, said colonial marines head back to LV-426 to investigate a distress signal sent from the USS Sulaco ("USS" or whatever they use for warship designations in the Aliens universe - I tried looking it up to no avail). Once the new batch of space marines arrive, they are of course set upon by Xenomorphs and hilarity ensues. Well, maybe not hilarity, but you get the idea. Just watch the trailer.