After settling into his new apartment, Maeda is greeted by an unexpected visitor - a charming middle schooler named Chie Satonaka who reveals herself as his new landlord. Maeda is thrilled at the sight of his youthful landlord, and his excitement only grows when he meets his stunning new neighbor, Reiko Shirai. Ooyasan wa Shishunki! follows the everyday lives of Maeda and his new acquaintances, as they navigate each day with the potential for new experiences and deepening connections.