The heroine is a normal girl, until one day she is invited to another world and becomes the princess of the dream world, where people use dreams as the energy to live. One day, the dream world is being attacked by something called "yumekui" ("dream eater"), and many princes are being attacked by it. The heroine must wake them up to save the dream world, as the princes are unable to wake up due to having their dreams stolen.

In this world, angels, demons, and other supernatural beings peacefully coexist with humans. Neil Bowman is a demon who is unlike most; he is mesmerized with human culture, and no matter how hard he tries, he can't do anything evil. Thus, he runs away from Hell and up to Earth. Neil moves in with his online friend and vampire, Ira Blood, along with Ira's many roommates. Despite coming to Earth to meet humans, Neil discovers that not a single one of his new roommates is actually human. Along with Ira, there's Lynn Angel, the stern angel landlord; Lynn's little sister, Lily, who falls from Heaven; Abu, a mummy who never speaks; and Vladimir Eliot Kirilenko, a werewolf tasked with monitoring Neil. What most of them don't realize—not even Neil himself—is that Neil possesses the powers of the Demon King. What effect will this have on the residents of Apartment 1031 on All Saints Street?

OVA bundled with 4th volume of manga.

Paradigm City, a city of amnesia and a place of belonging. It remains populated by forgotten pasts and the ruins of their labors due to a calamity 40 years ago. Shrouded in a fog-like mystery, it is up to people like Roger Smith to shine a light through the mist. Acting as a professional negotiator and suave agent, Roger is a self-tailored ladies man whose only love is for funeral black. However, as he gets deeply involved with his clients, what often starts as a simple negotiation evolves into Roger saving Paradigm from crime and peril. In the process, Roger stumbles even deeper into the untold folds of the city. As a rule, things are hardly ever as they appear. Serving as gray knight in a gray world, Roger is not without allies. By his side are Norman, a loyal and widely skilled butler, and Dorothy, a human-like android with deadpan snark. Together with the relic Big O, a jet-black mecha of gargantuan size and weight, they help Roger serve iron justice to Paradigm's lurking villains as he discovers the truth about 40 years ago. [Written by MAL Rewrite]