While walking home from high school, childhood friends Michiru and Taichi are suddenly engulfed in a mysterious light and find themselves trapped inside a strange locked room. A disembodied voice or message informs them that the only way to escape is to kiss each other on the neck. Desperate and embarrassed, they comply, only to discover that completing one task merely opens a door into another similarly sealed chamber, each with a new humiliating mission—such as sharing a bed or kissing again. The pair, who are close friends but not yet lovers, must navigate a series of these increasingly intimate challenges imposed by an unseen antagonist, all while grappling with their long‑suppressed feelings for each other. Their journey takes them through multiple rooms, each requiring a different form of physical closeness, forcing them to confront the awkwardness of their relationship and inch toward a deeper bond. The story follows their comedic, flustered attempts to complete each mission and escape back to the real world, culminating in a resolution that tests their growing connection.