Momo shares her secret harem plan with Nana. Nana, outraged, emphasizes that Rito already has Lala. However, Momo loves Rito too and the harem plan is the best solution. Nana walks down the hallway as she thinks about Momo's question regarding her feelings for Rito. Mea finds Nana depressed and talks to her. She knows about Momo's harem plan through Rito and finds it exciting. She shows Nana the benefits with her Psycho Dive but Nana stops it and questions her use of it at school. Mea doesn't mind since no one notices. Later, Nana finds Celine riding a vacuum robot made by Lala. Rito explains to Nana what happened earlier but Nana interrupts it with her firm disapproval of the harem plan. Meanwhile, Oshizu has been spying on Mea since morning and wonders if she can befriend her. As she approaches Mea, Mea teases Oshizu by disguising as Tearju and surprising her with a dog puppet, scaring Oshizu into releasing telekinetic powers. Oshizu then quits but Mea notes that she is one of the few people who knows her secret. Oshizu convinces Mea to stop hiding but Mea doesn't feel comfortable doing so. Suddenly, the vacuum robot goes berserk thanks to Oshizu's powers and sucks clothes everywhere it goes. Nana and Rito try to stop it as it zips through school. Oshizu asks Mea for help, but Mea fears revealing her identity and does nothing. In the end, Nana breaks the robot, unleashing a black hole. Oshizu tries to eradicate the black hole despite knowing that her lifespan will shorten from using too much power. However, Mea later admits blame for starting the mess and assists by using her charged shot. She ends up revealing her true identity but everyone applauds her instead. Yami also reveals that Mea is her little sister.