Sometimes the messiest problems aren't in your room—they're hiding inside your heart.
When transfer student Fumi Nishioka discovers a mysterious room hidden inside her new school, she finds herself attacked by strange creatures born from people's negative emotions. Luckily, she's rescued by Kyutaro Horikita, a student with an unusual talent for cleaning—and a secret life as a supernatural “Sweeper” who purifies troubled minds. As Fumi begins training alongside Kyutaro, she starts uncovering unsettling clues about her own forgotten past while forming an unexpected bond with her new mentor.