Mitsu was seeing off her son, who was supposed to go on a hot spring trip with friends. However, due to a sudden work conflict, his friend had to cancel, leaving Mitsu and her son to make the trip together alone. Worried that her son might be gay—thinking, "Could he be going to a hot spring with a male friend?"—Mitsu begins to subtly test him. The story unfolds as her maternal concerns blur into temptation, exploring how these hidden feelings shift the bond between mother and son. A warm yet heartbreaking tale of fleeting doubts and complex emotions arising from everyday family life.