Short-lived but fondly remembered sci-fi TV series aired on ABC from 1967-68 and focused on architect David Vincent (Roy Thinnes), the sole witness to a flying saucer landing and the only one aware of a plot by aliens who resemble Earthlings to infiltrate and take over the planet. Remember how to spot an Invader? (Clue: look at their little finger.) 43 episodes on 12 discs. 37 3/4 hrs.