What was supposed to be a fun visit to the karaoke studio suddenly turns into an emergency when the four friends are abducted by a shadowy organization.

Fuku-chan, Rikka's new space alien pet, has gone missing, and he's not just a harmless walking giant mushroom. Can Sekine stop him from devouring her friends, both figuratively and literally?

Time is running out. The lies are not holding. When the truths comes out, can the four kids remain friends? Can Rikka stay on Earth, without messing with the space-time continuum?