When the Hikari Studio appears in the World of Den-O, Tsukasa finds himself dressed in a strange detective-like attire with possession of a Rider Pass. He is then suddenly possessed by an Imagin, who battles a Mole Imagin as Kamen Rider Den-O. After taking out the Imagin, the possessed Tsukasa walks off until Natsumi uses her pressure point move to drive the Imagin out of him. When the Imagin known as Momotaros tries to possess Tsukasa, again, he throws Yusuke in front of him and Yusuke becomes possessed. After easily overcoming M-Yusuke and treating him to pudding for answers, Tsukasa learns that the Imagin lost his physical form some time before they arrived.