Reporter Tim O'Hara (Bill Bixby), while covering a flight of the Air Force X-15, finds a spaceship that contains a genuine Martian (Ray Walston). The Martian is a professor who specializes in the planet Earth and now has to repair his spaceship before he can go home.

Uncle Martin (Ray Walston) reads the mind of George, the dog owned by Tim's boss, and ascertains that the pooch is lovesick. The object of George's affections is Chloe, the dog next door, whose attractive owner Marsha Carson (Laura Shelton) despises all males thanks to an unhappy romance. In his efforts to bring George and Chloe together, Tim (Bill Bixby) also tries to turn the charm on Marsha--with interesting results.

Uncle Martin (Ray Walston) has trouble controlling his super-powers when he contacts the common cold, an affliction unknown on Mars. Fixing up a special pill to cure his malady, Martin leaves the powerful potion within reach of Tim (Bill Bixby), who accidentally consumes the pill and falls fast asleep just before he is to review an "outer space" exhibit at a local department store. Taking over Tim's assignment, Martin is appalled by the exhibit's glaring inaccuracies and pens a devastating article--thereby infuriating pompous store owner Trimble (played by former "Great Gildersleeve" Willard Waterman), who happens to be one of the biggest advertisers in Tim's newspaper!.

Uncle Martin finds out about the Government space strategy. He knows from experience that the plans are doomed to failure, but he finds no audience when he attempts to warn them.

Mrs. Brown's daughter Angela (Ann Marshall, in her final series appearance) is assigned to write a school paper on the theories of Professor Newton Jennings (John Fiedler), who believes that Mars is inhabited only by primitive amoebae and inverterbrates. Hoping to get the facts straight, Martin (Ray Walston) helps Angela finish her paper--and as a result, the girl gets a failing grade! Infuriated, Martin decides to expose Jennings as a fraud, but the results are not quite what anyone expects.

Seeking a brief respite from the Earth's variable oxygen, Martin (Ray Walston) climbs to the top of a water tower--and is immediately mistaken for a would-be suicide. Apprehended by the authorities and forced to see psychiatrist Dr. Bonnett (Frank Behrens), Martin attempts to wriggle out of the situation by reading the therapist's mind so that he will be certain to give the "right" answers. Unfortunately, Dr. Bonnett has other things on his mind, like his troubled marriage. ...and before long, the traditional doctor-patient roles are reversed!