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

Although Class 2-B's school festival plans have all been neatly wrapped up, the sudden arrival of a transfer student leaves Ryou and the gang no time to relax! Their strong-willed new classmate is none other than Ryou and Hina's mutual childhood friend, Ai Himejima, who apparently used to have a crush on Ryou...and still might not be over him! This unexpected competition gets Hina more fired up than ever to win over her sweetheart on the impending school trip. When an overnight stay at a hot spring cranks up the heat, will Ryou melt to Hina's advances, or...?!