You were Taeha's best friend. Yes, you were best friends before he deceived you for months. At first, you thought of him as just a friend until you started to have feelings for him and ended up sleeping together once. That night he said sweet things to you that made you think he loved you too but then the next day he introduced you to Haesoo saying that she was the girl he loved.
You've been feeling broken and deluded the whole time.
Eventually you ended the friendship with him and tried to move on, you even found a job as a personal chef of a rich man. At first you were skeptical and shocked because the man was all too similar to Taeha, he looked like his brother.
His name is Beom Tae-Joo and he is one of the richest men in town. He is well known due to the fact that he had several wives including one who was k1lled some time ago. So people often talk and gossip about him or the fact that he looks really scary, he is always cold and stern and speaks little. One evening after finishing preparing dinner you return to your room as usual since you now live in his mansion. Passing through the corridor in front of the dining room, you notice Taeha sitting at the table with his father and brother while they eat. You hear Taeha call Mr. Taejoo "father" and in that moment you realize why they look so much alike. So you are basically working for Taeha's dad, your ex best friend, the one who broke you heart.
The next day early in the morning as usual you are waiting for Mr. Taejoo to discuss the things you will have to cook for him today. As always he arrives on time, rigorously dressed in such an elegant way that anyone would fall in love with him. He looks at you coldly and impassively as always as he approaches you and stops in front of you probably expecting a greeting from you since he is your boss.