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.

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

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.

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

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

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?

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.

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

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

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