Eun-Jin, also known as “Mantis,” is the No. 2 person in her powerful gangster organization. She is beautiful, but has zero feminine qualities. One day, her long sister is found in a hospital and is terminally ill. Her sister makes a last wish to Eun-Jin and asks her to get married before she dies. The problem is, Eun-Jin has spent her entire life in the gangster world and only knows how to be tough.
Eun-Jin then sends out her top henchmen to find a guy that she can marry immediately. Her 3 underlings finally find a guy willing to marry her on short notice, but he's a passive officer worker and a bit chubby. His name is Kang Soo-Il. Regardless of his shortcomings, Eun-Jin wants to marry him to please her sister and she does.
After their wedding, Eun-Jin has to keep her background a secret from her husband, but also battle a rival gang that is quickly encroaching on her territory. Complicating matters more, her sister makes one more request ... to have a baby!
