Season 1 of In`youchuu The Animation premiered on October 31, 2006.

* Based on the erotic game by Tinker Bell.

Three students are in a school late at night fighting supernatural enemies. As they are about to leave, they get attacked and trapped.

Season 2 of In`youchuu The Animation premiered on April 25, 2008.

The demon hunters are back! Mikoto, Sui, and Takeru are sent to investigate a mysterious island where people have been disappearing repeatedly and dark yoma are rumored to be the cause. When the team first arrives it almost feels like a vacation to them, but it doesn't take them long to the feel the presence of something dark and evil ...

Season 3 of In`youchuu The Animation premiered on January 21, 2011.

For the final stage of their training as demon exorcists, sisters Mikoto and Takeru visit the village of Ayagami along with Yamato. Lurking within Yamato is a demon, sealed away by Hatsune, the girls' mother. However, to truly seal away this demon requires the ultimate spirit power of the Haramiko. For Mikoto and Takeru, no sacrifice is too great...

~ translated and adapted from official site by Cranston

Season 4 of In`youchuu The Animation premiered on August 4, 2017.

Mikoto and Takeru continue to be held as breeding stock for monsters after their demon-hunting mission went south, yet they hold out hope of Yamato rescuing them.