Prologue

Im Yoona is a cheerful young lady, who always always put the other first, making them her priority. She is kind and caring, and people often take advantages of her. Yet, there is a part of her that is still mysterious. She never talk about herself, neither about her parents. She is really superstitious and believes what people say easily, insisting that people don't lie to get advantage of her or to put her into danger. 
When she trusted someone she shouldn't have, she got involved with the powerful Ok Company's CEO, Ok Taecyeon, to whom she owes a few hundred thousand dollars. To pay him back, she will need to replace one of his workers, a worker from the 6th floor, in the company main building, from the Management Department. The worker who she will replace, have gotten into a big accident and is now in a deep coma. Yoona will work for the company, during the daytime, and her whole pay will go to Taecyeon. Not only that, during nighttime, she will have to go to her part-time job, where she can own money, to be able to pay her rent and her food. Luckily, she has a scholarship. For the nights where she doesn't have to work, she need to attend night classes to finish her last year in University, before she becomes an accountant.
Compared to Yoona, Taecyeon is a cold and calm young man. No one ever can guess what he is thinking and this was what made him the best business man around the world. He is cold and stubborn, but he is caring and kind. He doesn't have a good relationship with his mother. He is always followed by his secretary known as Mr. Kim, who helps Yoona a lot.
When they both were warned about a danger that awaits both of them and they decided to ignore it, they will then be facing problems... Big problems.
How will the two react then? What if past lives exist?