Taekwoon barely know that girl. What he know about her is she is the daughter of late Cha Dohyun, his father's bodyguard. That man passed away in his duty when he protect his father. It make his father feel guilty and promise to take care of that girl. 

But, Hakyeon refuse to live at Mr Jung's house and choose to stay at the orphanage. But, it does not prevent that man to keep take care of her like what he has promise to her father. He keep calling and meeting that girl until she enter the colleage.

Taekwoon barely know her but now, she is his wife and will live together under one roof.