After a routine raid, the rookie sky pirate Cou finds a most unusual cargo in his mates' cargo hold: Ren, an "Edel Reid", a race prized by humans for granting special combat power to their partners through "Reacting". He quickly discovers, however, that Ren is even more prized than he expected. The pirate ship is visited by three members of the Edel Reid Complete Protection Agency "Arc Aire", who try to purchase her. When Cou refuses, the ship is suddenly attacked by a mysterious force, and Cou's captain charges him with Ren's protection.
In this series, there are three human "species", humans, Edil Raid/Eden Reid and Sitting Raid. The Raids have magical power and can "react" with human beings. If they do so they become living weapons with several great abilities. Sitting Raid are artificially created Edil Raid. The sky pirate Could, the extremely stong and legendary, but newly awaken Edil Raid girl Ren and three members of Arc Aile, an Edil Raid protection organisation, are on a journey to the Edil Garden. On this "journey of love adventure" they experience many problems between the different species, because Edil and Sitting Raid are often used only as weapons, as well as fights between Arc Aile and "Chaos Choir", an organisation that wants the Edil Raid to rule the world. Due to the developing love between Ren and Could they can reunite humans and Edil Raid with an ancient song after many funny, exciting, but also tragic adventures. (Edil Raid songs, also called psalms, are used to set free immense magical power).