Even though Kokoro is dating a third-year boyfriend, she secretly has feelings for Yuki, who is on the same baseball team as him. During this time, she starts working as a manager. One summer day, while Kokoro is cleaning up the rooftop alone after club activities, they are suddenly hit by a torrential downpour. The door leading from the rooftop to the school building is locked. Kokoro has no choice but to enter the clubroom, and there she finds herself unexpectedly alone with Yuki, who has also been left behind. With weak cell phone signals making it difficult to contact the outside world, the two of them are alone in a small space... the young man and woman are laying down together in the uncomfortable humidity...