On a quiet night, young Milo quarreled with his mother. Feeling that the words were too hurtful, Milo decided to apologize to his mother when he saw a bright light in the dark and took her away. He chased all the way, boarded the mysterious spaceship and unexpectedly came to Mars thousands of miles away. It turned out that Martians grew out of the soil, and females living on Mars did not know how to take care of their children, so they invented a babysitter robot and hijacked their mother from Earth to extract her memory and experience into the robot's program. Milo learned from Grib, a human hiding near the Martian garbage station, that his mother's memory would be forgotten after it was extracted. With the help of Grib and Martian girl Kui, Milo embarked on an impossible mission to rescue her mother. The film is based on the original work of illustrator Berkeley Breathed.