3-ji no Itazura

Synopsis

I am a single, middle-aged man who leads a normal, stable life running my own dental clinic. After finishing my morning appointments, I was glad to see the cute, devilish girl who came into my clinic in the late afternoon. She asks me, "Hey, do you have someone you like? Do you know anything about uncle-niece marriages?" The girl is my niece, Koyune, a college student. Her eyes are teasing. Her attitude is bold and sometimes lewd. No, no, no… for me, Koyune is just my cute niece. Nothing more or less than that...! (Source: Kadokawa, translated)