Space Marines are sent to investigate strange events at a research facility on Mars but find themselves at the mercy of genetically enhanced killing machines.

Something has gone wrong at a remote scientific research station on Mars. All research has ceased. Communication has failed. And the messages that do get through are less than comforting. It's a level 5 quarantine and the only souls allowed in or out are the Rapid Response Tactical Squad - hardened Marines armed to the teeth with enough firepower to neutralize the enemy...or so they think.