Shotaro Tatewaki is the most ordinary and unremarkable senior high‑school student living in Asahikawa, Hokkaido. One day he was lucky enough to meet a mysterious and extraordinary person named Sakurako Kudo. Her extraordinariness can be attributed to her strange hobby: she is crazy about bones and is ready to spend hours searching for new specimens or caring for those already in her collection. In addition, the girl possesses outstanding deductive abilities, which means that together with Shotaro she often ends up at crime scenes and mysterious incidents that young people investigate with interest, shedding light on all the mysteries of what happened.