Supported by the NFS, the first responders confront the sinister mastermind in a decisive showdown.

Ho-gae delves into the investigation of Ma Joong-do's murder and reopens a past murder case and prison escape.

A bound corpse emerges following a serial arson. The first responders to unite in the investigation.

An unidentified body is found after a brawl at a junkyard. A crisis arises during the autopsy.

Criminals plan to endanger the NFS building. Can the team safeguard the place?

The police and fire department respond to an urgent call about a horrifying incident regarding organ extractions.

Ho-gae vanishes after a caravan explosion. Amidst the chaos, a showdown is drawing near.

Ho-gae's house is said to be haunted. He and Do-jin try to solve the mystery that lies in the ashes.

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

Two fires break out in different locations. The first responders find themselves in a crisis.

When a murder occurs at Myeong-pil's villa, Ho-gae leaves his post and joins the case. Kang Do-ha joins the National Forensic Service.

Do-ha concludes that the death at the villa was an accident, but Ho-gae continues his investigation. Do-ha uncovers the dark side of the neighbours.

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.

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.

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

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

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

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

The first responders and the NFS cooperate to uncover clues to the serial arsonist.

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

The arsonist's final plan gets revealed. Can Ho-gae save everyone from danger and catch the criminal?