Kokoro was dating her boyfriend from the third year while secretly harboring feelings for Yuuki Hoshimiya, who was also in the same baseball club. Around this time, she started working as a manager. One summer day, after club activities, Kokoro was alone cleaning the rooftop when suddenly hit by a heavy downpour. The door from the rooftop to the school building was locked. With no choice, Kokoro entered the club room and found herself unexpectedly alone with Yuuki, who had also been left behind. In the narrow space, with poor cellphone signal making external communication difficult, the two of them were together... The young man and woman were entwined in the uncomfortably humid air.
