Arakawa Under the Bridge

Kou Ichinomiya is raised according to one strict rule: never owe anyone anything. When he falls into the Arakawa River and is rescued by a strange young woman named Nino, he suddenly owes her his life and insists on repaying the debt by any means necessary.

Nino's request is simple and terrifying to him: she wants Kou to become her boyfriend. He moves into the community beneath the bridge and discovers that Nino, who claims to come from Venus, is nowhere near its strangest resident. Surrounded by a man dressed as a kappa, a priest in a nun's habit, musicians, fighters, and other eccentrics, Kou tries to impose logic on a world that does not care about his logic and slowly learns that relationships cannot be settled like invoices.