Martin and Andy (Andromeda) play tennis, Martian-style. Detective Bill Brennan and his son Brad try to spy on them. Non-human Andy is worried about a medical check-up at school. A robot duplicate creates issues at the school.
Andy has to do a school report on a planet. No one believes the truth about his home planet of Mars. After a disagreement over the matter he gets expelled. Insanity ensues.
Andy is feeling homesick. After missing curfew, Andy and Katie are grounded for a week. They sneak out in the spaceship for a quick trip to Mars. The Brennan's snoop.
Katie wants Andy to ask her wall-flower friend Hildegard to the school dance. Andy uses his powers to decorate the gym for the dance despite the Brennan's interference.
Katy uses Martin's new time machine to do her Ancient History homework on Cleopatra. Cleopatra is accidentally brought to the present and tries to woo Uncle Martin.
Uncle Martin creates a robot to help repair the spaceship. Andy and Katy discover it and use it as a butler. Brad swipes the robot and takes it to the circus.
Martin's new NYSINYD machine makes things vanish. Andy's teacher meets with Martin about Andy failing History. Due to a mishap, the teacher disappears.
Martin experiments with a device to make plants happy. Chump gets into trouble and becomes depressed. Andy tries the happy device on Chump only for it to go awry.