After failing her interview and falling for a scam, Lee Mi-jin falls into a well and finds herself transformed, leaving her desperate to find a cure.

Mi-jin begins work at the Prosecution Service as Lim Sun, running into Gye Ji-ung again. He later investigates a crime scene that leads to a wild chase.

Mi-jin's brief encounter with the killer aids Ji-ung in his efforts to find him. Sun becomes Ko Won's source of comfort during his struggles at work.

Sun reports to duty in Ji-ung's office, where she tackles every test thrown her way. Ji-ung prepares Mi-jin for the dangers she may face as a witness.

Ji-ung looks further into Ko Won's attacker after suspecting something bigger afoot. Sun gets scolded by Ji-ung over a mistake — shaking her confidence.

Mi-jin faces a crisis as she begins to transform into Sun in front of Ji-ung. Later, they make progress in a drug case after confronting violent youths.

Ji-ung questions Mi-jin while Ko Won investigates Sun, both suspecting something's off. Sun encounters a dilemma when she gets drunk at a work outing.

After Ji-ung reacts unexpectedly to Mi-jin's move, she avoids him out of sheer embarrassment. Ji-ung decides to investigate a suspect in his own way.

The investigation into the hospital yields suspicious evidence. Ji-ung begins to feel uncomfortable about Mi-jin and Ko Won's relationship.

Baek Cheol-gyu looks into the connection between Sun and Mi-jin. During a raid at the hospital, Sun finds herself in a dangerous predicament.

Sun finds herself in a panic to save herself from Baek Cheol-gyu. But she later implores him for help when she realizes they may have a shared history.

As their romance blossoms, Mi-jin and Ji-ung navigate their complex relationship. Cheol-gyu requests a meeting with Sun to assist her with her request.

After Mi-jin oversleeps, she faces her family and Ji-ung as Sun — having to confront her secret. But soon, she deduces the identity of the killer.

As Mi-jin tries to save her father, she finds herself in danger — forcing Ji-ung to spring into action to track her down before it's too late.

With nothing left to hide, Mi-jin contemplates her future. After she testifies in her attacker's case, Mi-jin and Ji-ung reconsider their relationship.