The Perfect Relationship

Minjae is smart, handsome, and thoughtful. He wakes up early to cook Hyukjoon breakfast and
gets home early enough to make him dinner. He cleans around the apartment and makes sure
to take care of his adoptive father. And like any dutiful son, he wants to follow in Hyukjoon's footsteps and become a teacher. He'd make any father proud.
But Hyukjoon isn't proud of Minjae. Hyukjoon's son died years ago. And the one responsible for his death lives with him. Minjae isn't Hyukjoon's son. He's his target.

(Source: Lezhin)