In need of a big win at work, Na Je-hui plays on Koo Kyung-hi's strengths and weaknesses to enlist her help on a missing person's case.

Kyung-yi suspects there's more to this accident than meets the eye; reuniting with an old classmate, Song Yi-kyung hears about a former teacher's fate.

A news story about a criminal's light sentence establishes the next target for K, who sets the scene at a bustling university campus.

Santa's chase after K puts the team on high alert, especially Kyung-yi; a spooked co-conspirator distances himself from the criminal mastermind.

Jung Jeong-yeon thinks back to a traumatic incident in her niece's past; following a hunch that K might leave the country, Kyung-yi's team sets a trap.

Kyung-yi shifts through Yi-kyung's playbooks to find out the next target; an outcast's account takes the team to an IT company headed by a public figure.