Ceres is a magic swordsman who reincarnated into a fantasy world after his previous life as a forty-two-year-old husband and father ended. In his new life, he joins the hero Zect's party on a quest to defeat the Demon King. Despite being a capable and dependable member who often handles the group's logistics and emotional support, he is abruptly expelled from the party by the arrogant Zect. The other members, including Ceres's childhood friends, side with the hero and offer no defense, leaving Ceres alone and dejected.

With nowhere to go, Ceres decides to purchase a domestic slave to manage his household. At the slave market, he is shocked to discover Shizuko, Zect's own mother, being sold as a slave. Shizuko had been cast aside by her son and husband. Ceres, who has always been attracted to older women, buys her freedom and proposes a partnership. Shizuko accepts, and the two form a new adventuring party. They quickly develop a romantic and physical relationship, eventually marrying.

Encouraged by Shizuko, Ceres sets out to find the mothers of his former party members, who have also been abandoned or mistreated by their families. He locates Haruka, the mother of the archer Rida, and successfully recruits her. Shizuko, wanting Ceres to be happy, actively encourages him to take Haruka as a wife as well. Ceres then tracks down Sayo, the mother of the mage Mel, and Misaki, the mother of the cleric Maria. In each case, he negotiates with or purchases the rights from their former husbands, freeing them from unhappy marriages. All four women eventually become Ceres's wives, forming a household and a fully functioning adventuring party.

The story follows Ceres and his new party of older women as they take on quests, build a life together, and grow stronger. Meanwhile, the hero Zect's original party, bereft of Ceres's stabilizing influence and organizational support, begins to fall apart under its own dysfunction. The narrative arc includes Ceres buying the debts of his wives' former husbands and subjecting them to a form of karmic punishment by forcing them to work under harsh conditions, though his goal is less about direct revenge and more about correcting their behavior and securing a stable future for his family. As the party proves increasingly successful, tensions between them and the deteriorating hero's party continue to build.