Taekyung had a doubt and suspicions about his foster mother but can't do anything because he is powerless and he need that "family" to grow. 10 yrs later he found out who killed her teacher but still can't do anything about it. He was torn between his sick foster mother who turned out to be the murderer of his good and admirable teacher and Heesoo who is mentally unstable and possessive.
I fuckin hate that bitch she thinks after she killed mom she can rid of son I m kinda pissed at cha but his whole family is manipulating him so he is nowhere safe also for haesoo I feel bad for him but I hope he has become someone powerful so he can ruin her political career in broad day public eyes.

Spoiler
Seme stabbed Uke, damn and ran away for 7 yrs. ALSO, Uke's foster mother that bitch killed Seme's mother and Uke knew it but chose to not report it to the police because he's bitch foster mother have a cancer stage 3. He did persuade his bitch mother to confess but in the end, haist. 7 yrs later, Heesoo is back and ready to take his revenge. Also, that bitch foster mother of Uke got cured and running for elections.