The Girl I Saved on the Train Turned Out to Be My Childhood Friend, Vol. 7 (manga) — Kennoji

A new rival appears, and she's Ryou's other childhood friend?! The girls' battle for Ryou's affections heats up during an overnight school trip! When Ryou and Hina reunite with their old friend Ai, her forwardness leaves Hina scrambling. Now, our heroine must try desperately to close the gap between herself and her crush -- before he's taken by someone else! The stage is early summer, and the girls' sweet school life is about to be painted in new colors!