Tom and Jerry Blast Off to Mars!

Tom chases Jerry from their house across town toward the International Space Place. During a live speech, Tom is splashed with green paint backstage and both are mistaken for aliens. The staff try to capture them, but only Tom is caught and thrown out.

During the testing of dehydrated food at the base, Jerry knocks over a cup, causing the food to spill everywhere in an explosive mess. The staff rush to capture him, but they determine that only Tom can catch Jerry. They bring Tom back to the base and assign him a mission to eliminate Jerry.

Following the mishap, the staff decide that Tom is the only one capable of catching Jerry and recruit him for a mission to eliminate the mouse. Tom agrees and gears up for a high-stakes pursuit that will extend beyond their orbit. The assignment marks a shift from a simple chase to a full-on space-borne pursuit.

Tom and Jerry's chase escalates as they stumble onto a rocket and hijack it, setting course for Mars. The pair hurtle through space while the staff back at the base scramble to regain control. The chase abruptly becomes a journey to another world.

Arriving near Mars, they are joined by Peep the green alien, her alien dog Ubu, and three Martians. Jerry is brought to the Martians' lair where he is mistaken for the feared 'Great Gloop.'

After the misunderstanding is revealed, the Martians realize Jerry is not the Great Gloop. Tom, Jerry, and Peep decide to hijack a flying saucer and return to Earth to warn humanity about a Martian attack. The trio prepares for a risky escape from the Martians' lair.

Tom, Jerry, and Peep reach Earth with their warning and manage to thwart the Martians' initial threat. Just as they think they’ve saved the planet, a gigantic orange Invince-a-tron vacuum robot arrives and begins sucking up people.

To stop Invince-a-tron, they hatch a plan that uses a bone to force Spike into the machine's brain, triggering a malfunction. The Invince-a-tron is destroyed, saving Earth from immediate danger. Tom, Jerry, and Peep celebrate their unlikely victory.

In gratitude, the U.S. President rewards Tom and Jerry with a new Hummer. However, before they can celebrate, a newly repaired Invince-a-tron, now controlled by Spike, returns for revenge. The threat to Earth looms once again.

Peep flies in on a flying saucer to rescue Jerry from danger, but she leaves Tom behind to be chased by the Spike-controlled Invince-a-tron. The trio's triumph turns into a new peril as Tom is stranded while Jerry escapes.

In the epilogue, Biff and Buzz clean up the mess and admit they lied about there being no life on Mars. They argue about what to do next, while a horrified Tom remains pursued by the Spike-controlled Invince-a-tron toward the sunset.

Tom continues to be chased by the Spike-controlled Invince-a-tron as Peep and Jerry fade into the distance. The ending leaves both the crowd and Tom in suspense as the sunset closes on their adventure.