Gary carries out the final days of his lonely, five-year prison sentence aboard the Galaxy One, when he meets Mooncake, a little green alien, who has the galaxy's most dangerous bounty hunters chasing after it. Gary swears to keep Mooncake safe from the anyone who would do it harm. Little does Gary know, Mooncake is the world's most adorable planet-destroying super weapon.

Gary tries to hide Mooncake safely away on the planet Yarno. But instead, Gary and Avocato are trapped in a terrifying mind-puzzle, while Mooncake is taken from them, and forced to fight in a combat arena called the Deathcropolis.