Yuichi, who is about to take his university entrance exam. He had been doted on and close to his aunt Mizuki since he was little, but they became estranged after she got married. This time, due to the coincidence of his exam and his uncle's business trip, he will be staying in Tokyo for two nights and three days to take the exam, living under the same roof as his first love. His first love, whom he hasn't seen in a long time, seems to be having trouble with her husband, and unable to hold back his feelings when faced with her sadness…
