"The matriarch of the Amatsu clan has instructed Mai and Ai to guar Onimaro, a 21-year-old half-demon, at all costs. But Onimaro has become infatuated with the twin warrior and follows them everywhere!

"The sisters soon discover that Onimaro's demonic side has reached a crucial juncture in this development. If Onimaro selects the path of Darkness, he will become the next Demon Lord – a being of unparalleled power and evil. Realizing this, the forces of evil have dispatched demons to retrieve him, and to obtain fresh victims from the mortal world…

"Mai an Ai embark on a trip to the Tenjin Shrine – followed by pesky Onimaro – leaving behind the protection of their warded home and their most powerful weapons. After all, their training is nearly completed, and the shrine is guarded by powerful priests. What could happen?

"However, the shrine has been compromised by the forces of evil, and has become the focus for the interdimensional gate between Earth and the Demon World! Summoning Oniyasha-Doji to eliminate the interfering Amatsu sisters, the demons intend to capture the half-demon Onimaro, tipping the cosmic scales in their favor.