Brother-in-law's Youngest Daughter

From their college club days, a cohabitation began with Yeon-jeong, a female senior who had a crush on him, and Yeong-soo, the president of the club. Her circumstances were difficult, and she was taken to Han-soo for a while. What confuses Han-soo is Ha-yeon, the daughter of Yeon-jeong, who came home late.