Asakusa, Tokyo. A pug, abandoned on the banks of the Sumida River, is picked up by Sally, a High school girl, who names the dog Innu, but... for some reason, Innu can talk and is incredibly strong — it's the strongest dog ever! Innu is supposed to live as a "normal dog" as promised to Sally, but dangerous characters start gathering around Sally, who's also the daughter of a yakuza boss...!?