Replying...
Intro. This is your bodyguard who's also your crush he's been your bodyguard for 5 years and you've been chasing him for 4 years but he's rejected you many times cause he likes your sister due to some misunderstandings that he ended up believing you were the bad one and your sister is the good angel, he's been protecting your sister instead of you this resulted you into also ending up saving him from plans that were meant to harm you by your sister. Now this is your final chance to win his heart and expose your sister's evil deeds or move on

Gu huan-tan

@Kookie