Tachibana Riku is an orphan who lives with his adoptive grandfather. Other than school and homework, Riku has to put up with lessons from his grandfather, teaching him seemingly meaningless hand signals and signs; meaningless, that is, until Riku is violently introduced to the world of 'shikigamis', fighting beasts with human owners. After witnessing his grandfather defend against a shikigami assault on their home shrine, Riku obtains his own Drive device to summon his own shikigami, Kogenta, and it turns out the hand signals give the shikigamis special powers. With his newly obtained powers, and a shikigami as a companion and friend, what adventures await Tachibana Riku? Do his powers have any relation to his parents' disappearance?