This story is set in a rural branch school located in a dying village, depicting the daily lives of two high school students. With only two students enrolled, the school is destined to close upon their graduation. The protagonist, "I," and his friend "Ichika" grow increasingly bored with their routine, gradually developing an intimate relationship through sexual acts—though always stopping short of penetration. Their one rule is simple: no insertion, due to the fear of pregnancy. One day, however, "I" obtains a condom, attempting to take their usual relationship further—and everything changes. Explored within this isolated environment are the deepening bond between the two, their anxiety about the future, and their raw, genuine emotions.