The Girl I Saved on the Train Turned Out to Be My Childhood Friend (Manga), Vol. 1

When high-schooler Ryou Takamori steps in to save a girl on a crowded train, he never expected her to be his childhood friend Hina Fushimi. Though the two of them sit next to each other in class, they haven't spoken since middle school-but this heroic act might give Hina the push she needed to shorten the distance between them!