A prime suspect emerges, but things aren't what they seem.

The meaning behind the drawings on the puzzle pieces is uncovered.

An unexpected suspect is arrested, shocking everyone involved.

The final puzzle piece arrives will the team be able to catch the killer in time?

A puzzle piece arrives on the same day as a murder, and Hansaem suspects it’s no coincidence.

Hansaem makes a shocking discovery and becomes unsure of whom to trust.

A stunning truth behind the serial murders is revealed.

Ena and Hansaem warily work together to solve the case.

Detective Hansaem suspects Ena after she fails to remember anything about her uncle's murder.

Another puzzle piece arrives, and a new murder case unfolds.

As the investigation escalates, new suspects begin to emerge.