After facing massive destruction from a devastating war, the city Olympus has become the last stronghold as the center of command for the world. In order to protect the city from a group of terrorists known as the Argonauts, former LAPD SWAT member, Deunan Knotts, runs special military forces consisting of Biroids (cloned humans) and her cyborg partner Brialeos. Knotts must protect the city at all costs but is met with difficulties when Al Ceides, the Argonaut leader thought to be dead, resurfaces and causes problems. (Source: FUNimation)

Bundled with the 19th and 20th volumes of the Ao no Exorcist manga. The first episode is based on the second chapter of the second Ao no Exorcist novel Home Sweet Home. The second episode is based on the title chapter from the Ao no Exorcist: Spy Game novel.

The Layzner OVA serves as an alternative version of the TV series. The first episode, titled Eiji 1996, recaps the first part of the series (episodes 01-24). The second episode (Le Caine 1999) takes place after a time skip, and contains episodes 26 through 37 (episode 25 of the TV series, being a recap itself, is skipped here). The final episode, Seal 2000, is an expanded version of the final episode of the TV series (38) and features new animation and a longer epilogue.

As the grand festival of True Cross Academy draws near, exwires and exorcists alike combine their efforts to banish any demon that threatens the celebrations. Among them, Rin Okumura is tasked with exorcising the soul-devouring demon known as the Phantom Train alongside his brother Yukio and Shiemi Moriyama. During their mission, the Phantom Train escapes its tracks and begins ravaging True Cross Academy. In the ensuing chaos, Rin encounters a childlike demon he dubs Usamaro, and begins to develop an odd friendship with it. However, Usamaro's abilities might be far more sinister than Rin initially expected.