Synopsis: Kokodake no Himitsu

After mustering up her courage, Mari Kurusu confesses her feelings to her crush, Kuro Rouzen. But to her surprise, Kuro devours her love letter instead of reading it. Suspecting that he might not be available due to his current relationship, Mari starts to follow him after school. Eventually, she discovers Kuro fighting a monster with tentacles emerging from his head...