Voir The Outer Limits: The Complete Original Series - Episode 33

A quirk in time lands an soldier of the future armed with an incredible weapon and an exaggerated instinct to kill back to the present day. Government authorities apprehend him and hold him in custody for examination. They discover that he's the ultimate soldier trained solely to destroy his enemy...another futuristic soldier who has also returned from the future and is stalking him. Befriended by a scientist the Soldier is taken into his home. Later armed with the rifle he runs amuck. But he is persuaded not to harm anyone. Finally the Enemy appears bearing a futuristic weapon and mortal combat ensues.