On his first day, Detective Jin Ho-gae works jointly with firefighters to resolve a kidnapping case.

The first responders try to stop a suicide attempt, but the case turns out to be more complicated.

A driver is arrested after a hit-and-run accident of a child. A shocking truth awaits.

Ho-gae starts an undercover operation. He must stop a crisis that may result in mass casualties.

An unidentified body is found at the scene of a fire. An unlikely person is held as a suspect.

Ho-gae identifies a new suspect, while the case becomes evermore ensnared in mystery.

Ho-gae reinvestigates a murder case and gets help from Song Seol and Yoon Hong.

Firefighters rush to save a teenage girl attempting suicide. Police find a body of a newborn baby.

The first responders search for the father of the stillborn child. They then meet a strange patient.

Ho-gae misses Hyun-seo by a second. He and Seol pursue the evasive kidnapper.

A series of fire incidents occur. Do-jin suspects a chain arson and goes to see Ho-gae.