Signal is a drama that is never missed in a list of thriller recs. Although the MDL synopsis seemed a bit boring to me, I decided to give it a try.

Park Hae Young, a detective, has an open disdain for the police force in spite of working for them. He had witnessed cases being handled for the sake of it's completion and his very own brother framed for a crime he never committed.
Chae Soo Young, his senior and team leader is unforgiving to this attitude, but she realizes that he had more spunk in him. Her sunbae, Lee Jae Han had disappeared 15 years ago.
Fate intertwines the three of their lives after his walkie-talkie that was about to be disposed off is found by Hae Young… leading to a chain of events that create waves in the past and it's ripples in the future. As Hae Young and Jae Han solve the past and the present, Hae Young seeks the answer to Jae Han's disappearance.

Hold onto your seats, because Signal is a mixture of thrill, mystery, suspense, despire, melancholy and various other heart wrenching emotions. The first few episodes deal with regular gory and disgusting cases, both in the past and future timelines (connected by the radio transmissions between Hae Young and Jae Han). It is during the later episodes that the ultimate dark side of the plot is revealed: Jae Han's disappearance.

I did not care for any of the characters initially. We don't see the inner workings of several of them, including Detective Cha. All the events seen through Hae Young's eyes, and his hatred for the police, made him one of my favorite characters. I have never seen the leading actor's performance before, but I'll definitely be checking them out in the future. Jae Han was a typical tsundere puppy whom I grew to slowly adore over the course of time. I loved his bravery and tenacity when it came to solving crimes.
I enjoyed seeing the two sides of Soo Young —- the inexperienced rookie cop and battle hardened detective.

Particular praise for the actor who played Kim Bum Joo, an utterly despicable and corrupted Chief of their Precinct. I wanted him dead until the very end.
The rest of the cast delivered stellar performances, even the minor culprits who popped up.

I loved how every case was solved and handled. As usual, the cops got on my nerves more than the killers. The stress was 100% real and my blood boiled whenever the cases were overturned. I feared for the life of the characters. I hated the villains. I adored the glimpses of family, loyalty and affection that were strong backbones of this drama. The music, especially the BGMs were spot on - I can recall several scenes because of it.

Definitely a must-watch (or must try) for fans of crime and thrillers.