Choi Sooyoung is your average college student, trying to finish her college degree in time.

Or is she?

In reality, Choi Sooyoung is not your average college student.

She is actually an assassin, a vigilante.

Trained in the arts of stealth, disguise and fighting, together with her partner, a computer genius named Kwon Yuri, who is in charge of tracking down people,   they hunt down and punish criminals who have slipped though the government's own justice system. 

Both are members of 'Dante', an organized vigilante group founded by Yuri's father who is also the surrogate father of Sooyoung.

But what will become of their double identity lives when a person from the past have came back in the guise of Jessica Jung, an old friend who had just came back from America.  Will old flames and memories come back? memories of even before the two have sworn to become justices' hands?