In an alternative 19th century, Allen Walker is an Exorcist, a soldier of God who hunts devils and demons called "Akuma". Allen is soon sent, by his Master Cross Marian, to England, where the Headquarters of the Exorcists, The Dark Religious Organization, resides. Together with the other Exorcists, who each posses the power of "innocence", Allen must track down Akuma all over the world and kill their master, The Millennium Earl, before he destroys the world!

However, things are much more then they seem. There are higher-level Akuma who posses immense power and intelligence. Among these are those who are part of Noah's Family, a group descended from Noah himself. These individuals have allied themselves with the Earl, and combined with the decreasing number of Exorcists who are part of the Dark Religious Organization, Allen and his fellow Exorcists are in for a tough ride with a bleak future!

Opening Themes:

• "INNOCENT SORROW" by abingdon boys school (eps. 1-25)
  "Brightdown" by Tamaki Nami (eps 26-51)
  "Doubt & Trust" by access (eps 52-76)
  "Gekidou" by UVERworld (eps 77-)
  

Ending Themes:

• "SNOW KISS" by MNIRGILIS (eps. 1-)
  "Pride of Tomorrow" by JUNE (eps 14-25)
  "Yume no Tsuduki e" by surface (eps 26-38)
  "Antoinette Blue" by Kitade Nana (eps 39-51)
  "Anata ga Koko ni Iru Riyuu" by Rie fu (eps 52-64)
  "Wish" by Sowelu (eps 65-76)
  "Regret" by Hoshimura Mai (eps 77-89)
  "Changin'" by Stephanie (eps 90-)