荒川アンダー ザ ブリッジ

Kou Ichinomiya, heir to a corporate empire, lives by one rule drilled into him since childhood: never owe anyone anything. When bullies hang his trousers from a bridge over the Arakawa River and he falls into the water trying to get them back, a girl named Nino pulls him out. Asked how he can repay a debt he cannot stomach carrying, she tells him to love her. Kou ends up living beneath the bridge among the self-styled eccentrics of the Arakawa riverbank.