The First Responders

Both dramas deal with first responders or rescuers. There's a mystery in each, and all the people in the main cast have interesting back stories.

Both dramas also involve episodic cases and an overreaching arc, and the MCs bond over their problems and how they deal with them.

They share the same investigative plot while being first responders to a crime.
The Voice is centered on a crime investigative plot with emergency response being the foothold of its activities. The ML is dogged, stubborn but not clouded by his judgements (atleast for too long) while the FL has special abilities that makes her working as a first responder effective.
The same goes with THE FIRST RESPONDERS, though I must say the camaraderie and chemistry between the leads is more notable here than in the Voice.
All the same, they are both delightful drama series that a crime genre lover will love.

Both focus on police and have a "case of the week" sort of format.
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Fierce detective Jin Ho Gae is all about catching low-lifes. He solves cases with his excellent ability to grasp crime scenes, read a criminal's mind, and has a strong will to win. While the fearless firefighter Bong Do Jin, who seems cold on the outside, is nice to those around him, and he takes good care of victims. He rushes to fire sites without a moment of hesitation. Joining the duo is Song Seol, an empathetic paramedic who heals broken hearts while treating wounds.

- It revolves around the cops too(with firefighters and forensics also involved in First Responders), there are a wide variety of cases being solved throughout different episodes.
- The main character has a slightly rash attitude with a troubled family background.
- Both have a romance subplot

Live has better romance and character development, with more realistic perspectives while First Responders is a bit more light-hearted in its approach though the cases are serious enough in both.

Both has paramedic backgrounds in high risk fields. Alongside both are shows where they have strong group of main characters both female and male.

Both include firefighting as a central theme. BLue Flame Assault focuses only on firefighting but the first responders focuses on a range of different first responders.

If you like the first responders then you will definitely like trace drama also.

The differences are:
Trace is a cdrama and the first responders is a kdrama.
Trace cast only have detectives, a psychologist and a forensic science but the first responders have a detective, a firefighter and a paramedics.

Similarities are:
Both dramas have investigation and interesting cases.
Both dramas have ml as detective.

Anyway I will just say watch it you will not need to skip a lot in trace drama and if you like investigations then this is for you.

GSF - military police
TFR - paramedic, firefighter, detective

if you enjoy high risk job shows I reccommend both

It is also deals with peculiar cases in every episodes and Male lead has some past and he overcomes it by solving the cases . The team environment pretty similar and in First Responders it is much more fun and interesting. If you like crash , go for this .

P4J - medical coroner & prosecutor
TFR - paramedic & detective

mixing both law and medicine in both shows

Both shows include a firefighter and paramedic as the main characters.

If you like The Flaming Heart you'll like The First Responder

Similar in the way it includes a doctor and a member of the police force but in you are my hero the male lead is a swat member while in the first responder he is a dectective

They are both similar to eachother with the storyline and they are both kdramas that have the same stories which are similar.

Flex X Cop is def lighter, but they both focus on action and police officers working as a team to solve case with a side comedy of course.
The First Responders also involves firefighters and paramedics, and is much more of a thriller (and emotional) show.
The MLs are quite similar too.