A rocketship is wheeled over Bugs Bunny's hole. Hungover, he climbs out of his hole and right into the ship. Unbeknownst to the still climbing Bugs, the ship launches. When he climbs to the top and screws open the tip of the ship, he realizes he is in space. He is hit from behind by a satellite which carries him to Mars.
Bugs meets Marvin the Martian who is trying to blow up earth with the Illudium Q-36 Explosive Space Modulator. Bugs steals the modulator and Marvin uses some Instant Martians that grow when watered to try to catch him. Playing follow the leader, Bugs tricks the Instant Martians into flying off the road and falling through a trap door. Bugs then steals a flying saucer, and while passing Marvin, trades the modulator for the bottle of Instant Martians. The lit modulator soon explodes while Bugs is flying back to Earth. When Bugs arrives back at Earth he crash lands into the sewer. Bugs climbs out of the sewer, frantically replaces the manhole cover, and warns the audience, "Run for the hills, Folks! Or you'll be up to your armpits in Martians!", before taking his own advice as the Instant Martian antennas begin to sprout from every crack in the road.