The movie takes place in the year 2079. 45 years earlier, Earth was attacked by a hostile alien civilization from Alpha Centauri. A totalitarian global military government is established to continue the war effort.

The film follows Spencer Olham (Gary Sinise)—a designer of top secret government weapons. He is arrested by the military, led by Major Hathaway, on the suspicion of being a replicant created by the hostile aliens. The replicants are perfect biological copies of existing humans, complete with transplanted memories... and do not know they are replicants. Each has a small organic nuclear bomb in its chest where the heart should be and they are programed to detonate when they are in close proximity to their target.

Written by 	Philip K. Dick (short story)
Starring 	Gary Sinise, Madeleine Stowe, Vincent D'Onofrio

NOTE: One of my favored SF