University student Umi Asagi generously receives both presents and confessions from Kamibukuro-kun—a stranger who always wears a paper bag over his head. Despite his overly timid demeanor, he endlessly pursues the woman he loves most, following her anywhere she goes. However, her best friend views Kamibukuro-kun as a nuisance and his love as a stalking obsession. Ultimately, her companion strikes terror into Kamibukuro-kun, threatening him never to go near Umi again.

Like Umi's friend had hoped, Kamibukuro-kun vanishes into thin air. But all this time, Umi never believed that his acts caused her trouble; in truth, she looks forward to seeing his presence every day. When Umi backs herself into a corner, will Kamibukuro-kun come to her rescue?