One rainy day, the serious Professor Amamiya comes home and finds a young man named Naruse seeking shelter from the downpour by standing beneath Amamiya's roof. Naruse looks so much like Amamiya's past love that on a whim, the professor invites the young man inside to dry off. Afterwards, Amamiya refuses the young man's contact information out of politeness, but a month later, Naruse reappears. This time, he asks to spend the night...