"Bad Love" follows the lives of five people.
So Won is 29-years-old and has a high school level education. She works as a clerk at a fabric store. So Won possesses a bright and honest personality. Her dream is to become a designer. Her twin sister is Eun Hye. Eun Hye's personality is completely different from So Won's. Eun Hye is feminine and quiet. Both sisters were accepted into a university, but, due to their financial situation, only Eun Hye was able to attend. To this day, Eun Hye feels guilt about that.
Jae Hyuk works as a designer. He is the first son of Chairman Han, who runs the Noyoo Group. Jae Hyuk fell in love with Eun Hye at first sight and they live together despite objections from Jae Hyuk's family.
Jae Hyuk has a younger stepbrother, Min Hyuk. Min Hyuk desperately wants to receive recognition from his father. Meanwhile, Yeon Soo works as a contract employee at Noyoo Group. When she was little, she lived off So-Won’s family. She wants to have successful life, but, in reality, she is still poor.