We are sent back to the battlefield, as the Federation's best Mobile Infantry unit are slowly being overpowered by the killer bugs. They are light years from the nearest reinforcements and are trapped on a remote outpost. They set up protection around the post, keeping all the bugs waiting for them to leave. But now the enemy is in the outpost, in a way which they would have never thought of.
 
http://www.imdb.com/title/tt0367093/