Takeru Narehira, a delinquent high schooler, lands in a parallel version of ancient Kyoto after an accident pulls him out of our world. Almost as soon as he arrives, he meets Tsukimiya, the girl he has seen again and again in his dreams, but a black mist soon falls over the city and unleashes monsters called oni. Takeru and Tsukimiya are both killed. He then wakes in Denji Heian-kyou once more, two weeks before the mist first appears, and understands that he can go back in time. Here, sorcerers known as onmyōji wield mystical powers and pilot magical shikigami suits against the oni. Determined to protect Tsukimiya, Takeru sets out to train with Abe Seimei, master onmyōjutsu and become an onmyōji who can change the future. Expect an action series built on supernatural battles and a second chance at stopping the attack.