After a successful mission in which his partner, Warp Darkmatter, fell in battle, Buzz Lightyear vows never to put another partner at risk and works solo. This vow, however is challenged by Star Command who assigns young Mira Nova to be Warp's replacement over Buzz's objections. In addition, the LGMs suggest he tries a new robot for an assistant while a lowly janitor, Booster, has his dreams of joining the Space Rangers. Together, this group of disparate heroes find they must work together to save the galaxy when Emporer Zurg hatches his grandest scheme for conquest yet...