Adventure Time Vol. 7: The Four Castles is the seventh graphic novel in the Adventure Time series.
Finn and Jake meet the Guildmaster, who invites them into the Heroes Guild of the Manyverse, but first, they are to retrieve four artifacts for him.
Finn and Jake encounter a giant snake guarding a trove of gems. Jake is swallowed by the snake but manages to break free, defeating the snake and taking some gems back to the Tree Fort. The Guildmaster of the Heroes Guild of the Manyverse, wearing speakers strapped to his hips, grandiose orange armor, and sunglasses, visits their home and offers Finn and Jake a challenge. If they can recover four artifacts for him, they will be admitted to his guild. The first artifact, owned by the Ice King, is the Evercomb, the finest grooming tool in the Land of Ooo which, according to tradition, can only be wielded by the fairest maidens. After Jake is unsuccessful in his stealthy attempt to steal the key from Ice King, Finn attacks Ice King and unlocks his chest. They plunder the Evercomb and return it to the Guildmaster, who is staying at the Tree Fort with BMO.