Lena is the youngest officer of the Police Department of Seoul. The principal one. She is serious in her work. Serious in life, but somehow, her friends think she is too serious and that's why she didn't had any long term relationship. She had boyfriends, girlfriends, but no one stays over a month. Cause Lena is too into her work.

Maybe it's hiding a fear to be just alone like every day when she gets off ? Or just an habit of a one-night stand ? Who knows ? But Lena stays someone we can trust. And of course, she is very logical, intelligent and processing. Nobody doubt about her performances, even when she do profiles, she is an expert. That's how she imprison so many criminals.