Fubuki Momose, an athletic high school girl, is in love with the seemingly apathetic Shinichi Kawahara. Unbeknownst to her, Shinichi shares the same sentiment but hesitates to convey his true emotions. The state of their relationship changes dramatically when an earthquake causes their school building to collapse—trapping four students inside. Confined alongside Fubuki and Shinichi are Takaaki Tsumura, Shinichi's promiscuous best friend, and the younger and unfamiliar Mizuha Senju, who also harbors feelings for Shinichi.
Determined to find a way out, the four divide into two pairs to search for an exit. Fubuki soon confesses her love to Shinichi, which he immediately reciprocates. Although their romance seemed destined to blossom, Fubuki's heart is thrown into disarray after Takaaki accuses Shinichi of sexually assaulting Mizuha. As her suspicion only continues to grow, Fubuki finds herself being manipulated by Takaaki while Shinichi remains on the sidelines.