The game begins in 2401 when the space marine, Sergeant Cortez, is leaving the space station that he destroyed at the end of TimeSplitters 2. His ship crash lands on the future Earth and two fellow marines greet him. Sergeant Cortez follows his squad of marines through the valley and battles unknown masked figures and TimeSplitters. Cortez is then tasked with following the signatures in the past by time travel thought to be caused by the TimeSplitters. He then goes on a mission to go back in time to find a way to stop the TimeSplitters race from being created.