The Man from the 25th Century is a 1968 short produced by Irwin Allen. It was intended to be a spin-off of "Lost in Space" and a pilot for a new TV series, but the series never sold.
Synopsis.
As a child, Robert Prentiss was abducted from 20th-century Topeka, Kansas, by aliens who claim to be 500 years more advanced than humans. After years of training and conditioning, the adult Prentiss is sent back to Earth with a mission: To destroy Project Delphi and their system that prevents alien invasions. Prentiss, however, finds that he cannot allow the aliens to attack Earth, so he tries to help Delphi to repel them.
References.
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