With the sudden appearance of the Four-Dimensional Monster Bullton, the STORAGE base is thrown into chaos! Time and space become warped and twisted, transforming the STORAGE base into a dimensional prison. Meanwhile, Haruki is confronted with a mysterious phenomenon!

The day has come for Horoboros, a monster that Yuka saw as a child, to awaken from its long slumber! The key to appeasing the raging Horoboros lies in a mysterious word recorded in an ancient document. Yuka sets out to decipher this writing, but Kaburagi's dark power is reaching out to Horoboros...!