Boku ga Shiranai Kimi no Kao

Aoba, a third-year university student, is living with his childhood friend Shou, who is one year younger than him. Except for the small apartment they share, their life together was quite comfortable, but one rainy day, Shou came home soaking wet and crying, and ever since then, Aoba can't get that crying face out of his head.

(Source: Ichijinsha, translated)