Chinhage Jinaeja

Han-Su, a romance novelist who has always lived a solitary life. Then, out of the blue, his niece Mo-Na, full of cool charm, appears in his life. Thus begins the strange cohabitation between a childish uncle and his precocious niece. When will the two of them finally grow closer? Join Han-Su, Mo-Na, and their... utterly charming neighbors as we stay close today and every day!

(Source: Lezhin, translated)

Note: Includes two extra chapters.