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.

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

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

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

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

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

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.

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

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

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

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

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.

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.

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.

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

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

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

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