The Amagi Brilliant Park has used all its savings and there is no money left to keep it running. However, Moffle remembers about their friend Dornel, who got missing after searching for treasure in an abandoned area of the park, and Seiya, Isuzu, Macaron, Tiramy and Moffle leave to investigate. While facing several traps along the way, Isuzu and Macaron get separated from the others and discover that Dornel was hidden inside the cave all this time, indulging on several hobbies, while Seiya and the others confront Rubrum, the Red Dragon, and learn that Rubrum and the Diggeries, a group of mole-like fairies were running away from a tyrannical empire and given shelter in the park. Back to the surface, Rubrum and the Diggeries ask for a job in the park as well, and Seiya agrees, while all the items Dornel gathered during his absence are sold to pay for the park's expenses.