When Finn and Jake are approached by the mysterious Guildmaster, an adventurer claiming to represent the Heroes' Guild of the Manyverse, they're challenged to complete the Quest of the Four Castles to gain entrance to the guild and the right to train as "real" heroes. But there's something fishy about this quest, and something even fishier about this Guldmaster!

Illustrated by: Zachary Sterling, Scott Maynard