Namete, Kajitte, Tokidoki Medete

Haru is a first-year high school student who finds herself in an unexpected situation after mistakenly giving her love letter to Seishirou-lun, a notorious troublemaker at school. Despite her requests for its return, he refuses and claims she is now his girlfriend. He follows her around at school, takes her lunch, watches her closely, and engages in inappropriate behavior, including kissing her. He has even started staying at her home. Haru insists she is not his girlfriend and pleads for him to stop.