When the entire universe seems to "blink," the Enterprise suspects invasion but finds only Lazarus, a man who seems to alternate between two different extremes of nature. In time, "he" is found to be two twinned beings locked in eternal struggle between their matter and anti-matter universes — a rift Kirk must help seal.
Mike and Robbie each have dates the same night. Due to a mix up in names, Mike picks up Robbie's young date (Trudi Ames), and Robbie picks up an older woman (Carole Costello), meant for Mike.
Barnaby investigates a jealous husband who he believes murdered a man for having an affair with his wife. But did he murder the wrong man?
After learning she was adopted, an heiress seeks her biological mother; guest Eileen Brennan.
