The time is fifty years in the future. Ordinary fire ants have mutated: their reproductive rate has skyrocketed, and they are advancing around the world eating everything in their path. Human civilization is crumbling under the onslaught. What's left of the 45th Division struggles against hopeless odds to hold the Red River, in Oklahoma. Their numbers have been decimated, their equipment is worn out, their morale is shot. They can't endure any longer, but they can't retreat: this is our last line of defense guarding the Grain Belt. Lose that...

This is the last day of Mankind's last stand against Nature out for revenge.