| Director | Simon Wells |
|---|---|
| Genre | science fiction film |
| Runtime | 88 min |
| Country | United States |
| Budget | $150 million |
| Box office | $39.2 million |
Unbeknownst to humans, a technologically sophisticated society of Martians lives below the surface of Mars. Their Supervisor, while observing Earth, sees a mother persuading her son, Milo, to do his chores. The Martians decide to bring her to Mars, where her "mom-ness" will be extracted and implanted into the next generation of nanny-bots.
After being grounded for feeding broccoli to the cat, Milo upsets his mother by sarcastically stating that his life would be better without her. When he goes to apologize, he finds his mother being abducted by the Martians and stows away on their spaceship. On Mars, Milo is taken to a prison cell but escapes. While being pursued by the Supervisor's henchmen, he follows a voice that tells him to jump down a chute and lands in a lower level. There, he sees a trash-covered landscape that is inhabited by furry creatures.
Milo is whisked away by the creatures to meet Gribble, also known as George Ribble, the adult human who told him to jump down the chute. Gribble explains that the Martians plan to extract the memories of Milo's mom at sunrise, using a process that will kill her. Gribble, who is lonely and does not want Milo to leave, pretends to help Milo find his mother. His plan goes awry, leading to Gribble being captured and Milo being chased by the Supervisor's henchmen. Milo is rescued by Ki, one of the supervisors who raise Martian babies.
He returns to Gribble's home but finds him missing. Gribble's robotic spider, Two-Cat, takes Milo to the Martian compound where Gribble is being prepared for execution. Milo is captured by his henchmen, but Ki tosses him a laser gun, allowing him to escape. Milo and Gribble retreat to a lower uninhabited level, where Gribble describes his own mom's abduction and murder by the Martians twenty years before. Milo convinces Gribble to help him just as Ki finds them. They discover an ancient mural of a Martian family and realize that Martian children were not always raised by machines. Martian female babies are currently raised by nanny-bots, while the male babies are sent below to be raised by adult male Martians, the furry creatures.
Milo, Gribble, and Ki save Milo's mom before sunrise, causing the energy of the extraction device to short out the electronic locks to the control room. This lets the adult males and babies enter and run amok, attacking the guards and robots. Milo and his mom steal oxygen helmets and try to escape across the Martian surface. The Supervisor, while attempting to kill them, causes Milo to trip, and his helmet shatters. Milo's mom gives him her own helmet, saving Milo but causing herself to suffocate in Mars's air. The Martians are awed, as this is the first time they have seen love. Gribble finds his own mother's helmet and gives it to Milo's mom, saving her. Ki brings a ship for them to escape in, and the henchmen arrest the Supervisor, deciding that they now prefer the loving vision of family life.
Milo, his mom, Gribble, Ki, and Two-Cat travel back to Earth. Gribble decides not to stay because he wants to pursue a relationship with Ki on Mars. Milo and his mom return home just before his dad arrives.