The high concept of this series is The Fugitive meets Invasion Of The Body Snatchers.
Architect David Vincent (Roy Thinnes) sees a flying saucer land and learns that alien beings from a dying world intend to take over. Theyre able to look just like us, although some cant bend their little fingers (a comical, somehow sinister detail). A major influence on X-Files-style TV sci-fi, this was made in an age of standalone stories rather than series arcs, giving it a jittery intensity - any gains the hero makes are wiped out next week. Thinnes square martyr/nut is compelling, and the guest stars are creepy as aliens masquerading as anyone from businessmen to tassel-tossing strippers. The music, titles and slightly skewed direction all suggest a moment in pop culture when everyone had to admit there was something wrong in America.