Theodore, Dorothy, Jonas, Ursula, and Hugh have lived inside a cage their whole lives, cared for by a team of scientists who provided everything they could ever need. But their lives change overnight when the scientists perform an experiment to transform these five average lab mice into GEMs: genetically engineered mice. When they're launched into orbit, the mice learn that the astronauts plan to leave them on the International Space Station-forever. The G.E.M.S. must band together and use their unique mutations to survive in outer space and change their destiny.