A mindless, violent alien race known as "The Creeps" have begun raiding lone outposts, destroying their way to the center of the human population: The Home Cluster. Realizing the threat of the Creeps is too great for any one faction to control, the past enemies have banded together to fight the alien menace. Setting up advanced towers which have proven to be particularly effective against Creeps, it is up to you to pick a faction and fight for its survival!