Ouka Satsurikuin, Sonico's co-worker at the modeling agency, gets a job as the spokesperson of a new fat-reducing ointment. Ouka invites Sonico, Suzu, and Fuuri to join her on a VIP cruise to celebrate the product's launch. In a private cabin the ointment company's owner is confronted by one of her own staff, concerned that the product has had insufficient testing, she proceeds with the product release anyway. Ouka's roll-out presentation goes very well, with samples given to attendees who are pleased with the immediate results. That night, however, Ouka, Sonico and her bandmates find themselves on the run from the other passengers, who have effectively become zombies from the ointment's side-effects and are desperately hungry. With the cruise ship out at sea there are few places they can go to get away, which they must do until the effects of the cream wears off.