Yoshihito, an ordinary young man, is looking for a job to stabilize his life, and is trying to make a living by renting out a room in the house that his parents left him. With no resident and no hope of earning rent, he comes across a girl on the street who happens to be asking for directions...

After a long period of zero occupancy, his rented room finally has two girls moving in at once. One was a werewolf and one was a vampire.With him and other species, a strange shared life began.

Yoshihito finds a job and starts his life as a judge and landlord at the same time. One day, while having dinner with the residents, he is suddenly called by his employer. When he rushes to the place, he is suddenly subjected to body modification!

Returning from the dimensional world of dreams, Yoshihito's next mission is to find a new resident. He took Riri and Vivian and left for England in order to accomplish his duty as an examiner.

They came to England looking for a new resident. Information from the data source shows that the new resident is in Yafhrud. On their way, they meet the self-proclaimed demon hunter 'Nangoo Sanpachi' and together they head to Yafhrud Castle, where there are rumors of ghosts.

The seal of the demon was waiting for them when they reach the basement of Yafhrud Castle. They were mistaken as intruders who had come to break the demon's seal and now forced to fight with the defense system.

The new resident they met at Yafhrud Castle was Isaccs, the demon. When he returns to their home after a few days, Raven calls him back and introduces him to the new resident, "Satsuki".Together with May, Yoshihito and the others head off to outer space to meet the next resident!

The new resident seems to be on a planet 895 light years away from Earth. The trouble occurs during their way on their spaceship. The ship crashes on the target planet. When Yoshihito wakes up to find himself in the dimensional world of his dreams, a place he has been before.

The new resident was a mermaid's egg. Yoshihito took everyone and return to Earth on their spaceship "Dunkei Rockets". Just when he thought he had arrived safely and accomplished his mission, Riri suddenly went out of control. They decided to look for a way to bring back her consciousness.

Yoshihito and his friends brought Riri back to conscious from her atavismus. Although they returned home safely, soon they've been attacked by someone and Riri has been kidnapped. They use Vivien's bats to rescue her...

It was the werewolves who had abducted Riri. They were told that the day of Siren's prophecy day was approaching, and various races were gathering their friends before then.A group of demon hunters starts to attacked Yoshihito and his friends now knowing what's going on.

A group of demon hunters attacks them as they realized the gathering of various species. During the fierce battle, Satsuki is taken hostage by the demon hunter. However, when the self-proclaimed strongest demon hunter, Nangoo Sampachi appears, they are in an unexpected situation...!