The science club head to Lake Tobi to investigate reports of a mysterious creature terrorising the area. Unbeknownst to them two fellow students, Kurasawa Rikka (the Second Student Council President) and Mahiwa are also ine the area searching for the creature. It soon emerges that the monster is in fact a familiar that was abandoned by Mahiwa and has gone berserk. Armed with this knowledge the science club set out to reunite the two and stop the creature's rampage.