Mako Yanagibashi is a very ordinary girl.The person who suddenly appeared in front of her was Tsuzumi, the self-proclaimed (?) strongest five-tailed demon cat.Her purpose is to investigate the human world and complete "Manrokusan". Not wanting to get involved in her troubles, Mako tries to give Tsuzumi her latest device and let her go home, but...Tsuzumi is very excited about her first experience!! Mako falls in love with Tsuzumi, and she ends up helping him complete "Manrokusan" -!?