The Girl I Saved on the Train Turned Out to Be My Childhood Friend, Vol. 3 (light novel)

There's only one month left until the July field trip, and Hina Fushimi is still making
enthusiastic advances on Ryou Takamori. But when a girl named Ai Himejima, another
one of Ryou's childhood friends, transfers to their high school, Ryou and Hina's
relationship hits a snag. Faced with a rival in love, Hina redoubles her efforts to win
Ryou over by resorting to even bolder feats of flirtation. Ryou, meanwhile, continues to
act completely oblivious!