Otome no Chikyuu no Hashirikata

Ayumi Miyamura came to Mt. Mitake in Okutama, Tokyo to lose weight. On her way to the trailhead, she encounters a strange runner who dashed past her and entered the mountain from a back road. Unbeknownst to her, this was her first encounter with a map and compass, and the start of her quest to participate in an "adventure race."