Assistant prosecutor Eun Bong-hee and prosecutor Noh Ji-wook get off to a bad start, as she accuses him of touching her inappropriately on the subway.

Bong-hee begins her internship at the prosecutor's office and is shocked to learn that she will be working under Ji-wook.

Bong-hee and Ji-wook find themselves on opposite sides of the law when Bong-hee gets accused of murder and Ji-wook is assigned to prosecute her case.

Ji-wook comes across a critical piece of evidence, a bloody knife, that could have a great effect on the case. Bong-hee's trial commences.

Bong-hee tries uncover the true identity of Hee-joon's killer, with a melody as her only clue. Ji-wook has difficulty adapting to his new job as a defence lawyer.

Bong-hee and Ji-wook appear in court representing opposing clients, but realise they need each other's help when things take a turn for the worse.