Hikaru Nagi is an ordinary elementary school student living in Kyoto . One day, he meets a mysterious girl "Kukuru" who is targeted by aliens at Kuraiji Temple, which he visits to cover his homework. Recognized as her partner for helping her, Nagi receives her power and transforms into the legendary warrior "Homura no Kimi". Kukuru and Nagi go to war against aliens over Kukuru's ultimate power "Akasha".