Based on DECO*27's popular Vocaloid song "Mozaik Role." Megumi Nakashiro never believed in doppelgangers or any of that occult stuff. Sure, she was a member of the occult club, but that was only because her boyfriend Kubohara was in it. However, her view starts changing when her boyfriend suddenly disappears and a girl named Megumi Kokusenya joins her class..