When the group arrives in Zircon Tower City, a child named Horn offers to be a guide to the dungeon; the description confirms it is Diablo's dungeon. Later, a monstrous sand whale attacks the city and Diablo tries to fight it, but requires the help of Batutta and the city's leader, Fanis Laminitus.

The group arrives at Diablo's dungeon and have to go through several rooms filled with mazes, monsters and lava.