Tengoku no Monban

Immediately upon setting off on a cross-country tour of Japan, Kitahara Minami finds himself flung from a boat by a gorgeous woman he's only just met. He manages to swim to a distant shore, only to find a young man in glasses waiting for him there, telling Minami, "You passed." Because Minami made it to the island alive, the young man agrees to hire him, revealing that he's actually the guard (owner) of this paradise island, Tenma Yuunagi. Minami is dumbfounded to be told, "Starting today, you're my servant!" Minami starts his new job on the island, working alongside the bird- and beastfolk who live there--and one evening, he spots Yuunagi bathing in the ocean alone. Yuunagi explains that this is a purification ceremony, to ready himself for a 'customer'. But what exactly does he mean by 'customer'? And what exactly is this island here for? Minami is awhirl with questions...