While travelling across Japan, Kitahara Minami is pushed off a boat by a beautiful woman he met for the first time. After managing to swim to an island, Minami comes across a bespectacled young man who pronounces, “You pass.”

The young man, Yuunagi Tenma, is the owner (guard) of Paradise Isle and since Minami reached the island without dying, he qualifies to be hired. A stunned Minami is told by Yuunagi, “From this day forth, you shall be my manservant!”

So he starts working on the island alongside beastfolk, some of whom are part-dog, others part-bird.

One day Minami spies Yuunagi bathing in the sea at night. Yuunagi says it is a ritual to welcome ‘guests’ (customers). What exactly does Yuunagi mean by 'guest’, and what is the purpose of the island? Puzzled by all these mysteries, what will Minami do?!