 During peace in 1725, aging swordsman Isaburo is living a henpecked life when his clan lord requests that Isaburo s son marry the lord s mistress, with whom he s displeased, even though she s born him a son. Isaburo wants to refuse, but his son Yogoro accepts the woman, Ichi, and they fall deeply in love. Their love renews Isaburo, so when the clan lord s elder son dies and the lord sends for Ichi to return to his side as mother of his heir, Isaburo opposes his lord. Yogoro and Ichi, who now have a baby daughter, stand with him. The clan orders their suicide, then sends soldiers to kill them. Isaburo s only hope is to take his case to Edo to expose the clan s cruelty. Can he?