Kazuma Hoshino is a young student who, in the company of his younger brother Ayumu, move from undisclosed urban Japan into the rural city of Yamabiko. On their way to Yorozuyo Inn, where they are prearranged to lodge, the boys get on the wrong bus, forcing them to wait out the next ride at a stop. Lounging around and passing time, a wild monkey mischievously steals Ayumu's hat, and an upset Kazuma gives chase into the surrounding forest.

Minutes pass, and though scuffed and worn, Kazuma is able to recover the hat to the realization that he is lost. Ui Nakatsugawa, a schoolgirl, happens upon Kazuma and happily leads him in the direction of the bus stop, skipping across a river he'd passed earlier with ease. Encouraged by her to do the same, Kazuma lands wrong, causing him to tackle Ui to the ground with a kiss. Having been seen and scolded by her friend Ibuki Hinata, Kazuma leaves, disheartened that his time with Ui was momentary.

The following day, having moved into their room at the inn, Kazuma and Ayumu head to their new school, Yamabiko South Academy. Much to his surprise, it is during his introduction to the class that Kazuma meets Ui and Ibuki again.