One week after Otosaka Ame starts high school, he happens to glance down the hallway and spots a familiar face—Karakisaki Umi, a classmate from the same middle school who had mysteriously stopped showing up right after the school year began. Even when she does come to school, she avoids eye contact, forces a polite smile, and keeps her head down. Concerned, Ame decides to reach out to her...