Ko Ichinomiyo's life has taken a turn for the worst or is it the best? After being rescued from his death, he has found himself inexplicably in debt to his saviour. The girl named Nino, a self-proclaimed 'Veusion', however, has no interest in his money but instead would like him to become her boyfriend instead.

Now he's living with her under the bridge at Arakawa River far away from modern civilisation and now he's just met the neighbours. Featuring a centuries old kappa, a cross-dressing nun, a rock star with a literal star for his head, all of whom make Nino seem normal, Ko just might be in over his head.

Welcome to life Arakawa Under the Bridge!