Before 'Squid Game' Took Over the World, This 16-Part Sci-Fi Thriller Was Already a Phenomenon

2 weeks ago 11

Published Feb 12, 2026, 8:20 AM EST

Giovana Gelhoren is a High-Trending Topics Writer at Collider, covering the most-talked-about stars, movies, and TV shows. Before joining Collider, she was a Digital News Writer at People Magazine and served as Associate Editor at SheKnows, where she honed her expertise in celebrity coverage and entertainment journalism.

A proud Latina from Rio de Janeiro, Brazil, Giovana graduated from Northwestern University with a degree in Journalism and International Studies. She has interviewed countless celebrities, including Anne Hathaway, Halle Berry, Pamela Anderson, Jamie Lee Curtis, and Brenda Song, and is known for her encyclopedic knowledge of film, TV, and pop culture.

Detective crime shows are everywhere. From True Detective to High Potential, shows about investigating a murder, or murders, always make for good TV. In each of these shows, whether it's through the case itself, the tone of the series, or the impeccable acting, they all find their own lane, making audiences tune in even though they might've seen a few shows of the genre already. That's definitely the case of the 2017 crime series Tunnel, which perfectly blended being a detective series with a sci-fi edge. The Korean series, which was released just a few years before the Squid Game phenomenon, was a hit with viewers in its own right.

What Is 'Tunnel' About?

Yoon Hyun-min and Choi Jin-hyuk in Tunnel.

Tunnel starts off with a successful homicide detective named Park Gwang-ho (Choi Jin-hyuk) in 1986. When he becomes the lead investigator in a serial killer case, one in which the killer marks its victims with dots on their ankles, tensions rise as he struggles to find clues with bodies piling up left and right. Then, one night, while chasing the supposed culprit, he passes through a tunnel and time travels more than 30 years into the future all the way to 2017.

While trying to reconcile with what happened, Park rejoins the police force and meets his new partner, Kim Seon-jae (Yoon Hyun-min). Despite some hostility at first, the detective duo soon begin to gel and continue to investigate the same serial killer, who has now continued his killing spree 31 years later. They also recruit the ice-cold criminal psychologist, Professor Shin Jae-yi (Lee Yoo-young) to help get some answers. The series also stars Kang Suk-won, Han Yeo-wool, Jo Hie-bong, Kim Min-sang, and Kang Ki-young.

Gong Yoo as the Salesman buying bread in Squid Game Season 2.

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'Tunnel' Has Become a Must-Watch Crime Drama

While Tunnel has yet to receive a score on Rotten Tomatoes, the series has been a beloved fan favorite since its release, reaching an impressive 8.2 score on IMDb. Among the highlights is how the show cleverly approaches the time travel elements, with Park figuring out how the past can affect the future and how he can use his new abilities in his favor to solve crime. By doing so, the show makes the best of its sci-fi component, adding an element, much like Korean drama Signal, that makes the investigation engaging, constantly developing and unique to other detective shows on TV.

Reviews have gone on to call Tunnel one of the best Korean dramas available, one that pushes the envelope in multiple genres while still executing it all with sharpness, intensity and ease. "Well acted, great direction, and music score — this show has everything from comedy to suspense and is definitely worth watching," writes one review. "This show has everything," echoed another. "Crime, drama, emotions, well-structured story, great acting... It's a hidden gem and you won't be disappointed."

With that said, while detective crime shows are certainly not uncommon on TV, 2017's Tunnel is a must-watch for true-crime and Kdrama fans alike. With a sci-fi, time-traveling element, the series sets itself apart from other crime dramas as it follows a mystery inside a mystery, and sees the main character come to terms with his new reality, all while sparing no expense in finding the decades-long killer. It's engaging, gripping, and seen as one of the best Korean crime dramas of all time.