Ame to Umi

It’s been a week since Ame Otosaka started high school. While glancing down the hallway, he catches sight of a familiar face: Umi Karasaki, a classmate from his middle school who had been absent without notice since the very first day of term.
Even when she finally makes it to school, Umi remains a mystery: always looking down, hiding behind a mask of polite, empty smiles. Concerned, Ame decides to reach out and speak to her...

(Source: Shueisha, translated)