It follows Yakumo, whose father is the priest of the Taihaku Temple in Kyoto. Yakumo's father Monju, once battled using Shikigami, a ritual god that makes contracts to fight alongside humans. However, while Yakumo is outside one day training to be like his father, Monju is attacked. Rushing in to help him, Yakumo desperately makes a contract with Kogenta, a white tiger Shikigami and the same one that his father befriended many years ago. The series chronicles Yakumo's attempts to train with Kogenta at their temple and to master a power known as the In.
The Onmyou Taisenki manga and television series tell a completely different story, set years apart from each other and with new protagonists. The only reoccurring characters are the Shikigami, such as Kogenta, who fights alongside the protagonists of both series.
This manga provides examples of:
- Clap Your Hands If You Believe: Yakumo in the beginning of the series wants more than anything for Shikigami and Toujinshi to be real, even skipping school to pretend he is a Toujinshi and practice.
- Taken for Granite: At the end of the second chapter, Yakumo's father is turned to stone. It's even more heartbreaking that it happens immediately after his reunion with Kogenta.
◊ - Talking Animal: Kogenta, and many other Shikigami in the series are anthropomorphic animals capable of talking to their Toujinshi, as well as others.
