The episode begins with Mickey running inside Funny to show his friends the new Rocket Mouse book he got in the mail. As soon as he opens it, it reveals a video of Rocket Mouse asking the friends to come visit him for help on a space mission. Funny transforms into a rocket ship and blasts off into space.
As soon as the gang arrives at the space station, Rocket Mouse explains that he plans on building a base on a nearby planet to study it better and needs the gang's help assembling it, saying they'll earn mouse-stronaut badges for a successful mission. Minnie and Donald volunteer to assemble the base, Daisy and Goofy volunteer to use jetpacks to push the base into position, and Mickey volunteers to use the space rover to clear the debris out of the way. Before descending on the planet, Rocket Mouse warns everyone to beware of Cosmo Cockroach, a tiny cockroach who often causes trouble by stealing shiny objects that don't belong him.
The gang soon descends on the planet. As Funny heads back to the station to refuel for the trip back home, Minnie and Donald begin assembling the base, Mickey begins using the rover, and Rocket Mouse teaches Daisy and Goofy how to use the jetpacks. As Mickey is driving the rover, however, Cosmo Cockroach appears and steals one of the back lights, causing it to malfunction and drive itself into a pond of mud. Cosmo Cockroach then steals the blue pin off of Rocket Mouse's jetpack, causing it to fly out of control. As Goofy and Daisy fly off to rescue Rocket Mouse, Mickey uses the rover's anchor to pull itself out of the mud before using the claw to catch Rocket Mouse. Rocket Mouse then strikes up a deal with Cosmo Cockroach: if he returns the stolen items and apologizes, he will receive something shiny in return.
The team finishes assembling the base with Cosmo Cockroach's help and receive their mouse-stronaut badges. Rocket Mouse tells that he will call them for more missions as he returns to the space station and the gang returns for home. Funny presents a trophy to remember their trip while Mickey and Minnie wave goodbye to the viewers as the episode ends.