Introduction
What if someone could steal not just your money, but your entire identity — your name, your face, your proof that you even exist? Mousetrap takes that genuinely unsettling premise and roots it in a centuries-old Korean folktale, pairing Ryu Jun-yeol and Sul Kyung-gu for the first time on screen in a paranoid, technology-driven identity-theft thriller that’s already generating strong buzz ahead of its Netflix premiere.
Quick Facts
| Category | Details |
|---|---|
| Korean Title | 들쥐 (Deuljwi / “Field Mouse”) |
| Also Known As | The Rat (working title) |
| Based On | Kakao webtoon Field Mouse by Ludovico |
| Director | Kim Hong-sun |
| Writer | Lee Jae-gon |
| Starring | Ryu Jun-yeol, Sul Kyung-gu, Lee Kyu-hyung |
| Genre | Mystery / Thriller / Crime |
| Episodes | 10 |
| Rating | TV-MA |
| Platform | Netflix (Original, Limited Series) |
| In Development Since | December 2024 (casting talks first reported) |
| Original English Working Title | The Rat |
| Netflix Slate Announcement | January 2026, as part of Netflix Korea’s 2026 slate |
Casting and Production History
The road to Mousetrap‘s premiere stretched back nearly two years. Ilgan Sports first reported in December 2024 that Ryu Jun-yeol and Sul Kyung-gu were in early talks to lead the series; by May 2025, both actors were officially confirmed. Supporting cast members Moon Jong-il and Go Hyung-woo joined in December 2025, rounding out the ensemble. The project was formally unveiled as part of Netflix Korea’s 2026 slate in January 2026, initially given a general “third quarter of 2026” release window before Netflix confirmed the specific August 28 premiere date at the end of July 2026 — meaning fans tracking the project had a fairly firm sense of its release timing for about a month before the official date landed.
Character Deep Dive
Je Moon-jae (Ryu Jun-yeol) — A reclusive novelist whose entire life is built around careful control and routine, a coping mechanism for his severe social anxiety. Ryu has spoken about the character’s relevance to modern life, noting: “I thought that the reality of modern society, where we have no choice but to define ourselves through a few things — our outward appearance, identification cards, and the things that prove who we are — is well reflected in Mousetrap.”
No-ja (Sul Kyung-gu) — Introduced as a calm, dangerous loan shark who also runs a private detective agency, willing to do virtually anything for money. Crucially, No-ja isn’t a neutral ally: he’s been hunting Moon-jae for three years after Moon-jae borrowed money from him and disappeared, meaning his motivation to help track down “the Rat” is initially rooted in wanting to recover what he’s owed, not altruism. That tension — a man forced to rely on someone actively pursuing him for a debt — is a big part of what gives the central partnership its edge. Sul, who has built a Netflix résumé including Kill Boksoon, Mantis, and The Whirlwind, described the show’s premise as chillingly plausible: “There is something chilling about how easily a person can be socially erased when they are not authenticated within a notarization system.”
Lee Kyu-hyung — Rounds out the principal cast in a supporting role; the actor has also spoken publicly about the story’s real-world resonance, saying the overwhelming amount of personal information available today means “someone could take my life away from me if they really set their mind to it.”
Overview
Je Moon-jae (Ryu Jun-yeol) is a reclusive novelist dealing with severe social anxiety, living a carefully controlled, isolated existence. That fragile stability shatters the day his fingerprint recognition suddenly fails, locking him out of his own phone, apartment, and bank account — and the one friend who managed everything for him vanishes without explanation. With no way left to prove he is who he says he is, Moon-jae discovers that a mysterious figure known only as “the Rat” has stolen his name, his identity, and his entire fortune. Desperate to reclaim his life, he tracks down No-ja (Sul Kyung-gu), a calm, dangerous loan shark who’s been hunting Moon-jae for three years over an old debt — only to find their goals suddenly, uneasily aligned against a common enemy.
The Folktale Behind the Story
Mousetrap‘s premise draws directly from a traditional Korean folktale sometimes referred to as “The Field Rat That Ate a Fingernail.” In the original tale, a field rat sneaks into a home and eats a person’s discarded fingernail clippings, absorbing enough of that person’s essence to transform into an exact physical duplicate — capable of infiltrating and eventually replacing the real person’s entire life, family, and identity, since fingernails were traditionally seen as carrying a piece of a person’s spirit or fate. Promotional stills for the series lean directly into this imagery, showing Moon-jae in the act of cutting his fingernails, as well as a tense standoff between Moon-jae and “the Rat” across a barbed-wire fence — visually reinforcing the folktale’s DNA within the show’s modern setting.
Rather than playing this as supernatural horror, the series translates the old folktale into modern psychological horror, built around technology, personal data, and how easily a person can be erased in a world where identity is verified through phones, fingerprints, and digital records rather than who someone actually is. Director Kim Hong-sun has said plainly, “Similar things are already happening, and as more and more people are living alone, I think this is something that could realistically happen” — grounding the folkloric premise in very real, very modern anxiety. It’s a smart piece of adaptation: swapping literal shapeshifting for identity theft via stolen biometric and digital data keeps the folktale’s core fear (someone else quietly becoming “you”) while making it feel entirely plausible in a contemporary setting.
Highlights
- The first on-screen pairing of Ryu Jun-yeol and Sul Kyung-gu, two of Korea’s most respected actors, whose dynamic anchors the entire series.
- A genuinely unsettling, technologically-grounded take on an old folktale, translating supernatural horror into modern paranoia about digital identity and data.
- Strong thematic resonance — cast and crew have spoken candidly about how the story reflects real anxieties about identity verification and social erasure in an increasingly isolated, digitized society.
- A tight, mystery-chase structure, keeping the central question of the Rat’s true identity at the center of the show’s tension.
- Adapted from a well-regarded Kakao webtoon, giving the series a strong narrative foundation.
Pros & Cons
Pros
- Ryu Jun-yeol and Sul Kyung-gu’s chemistry is a genuine draw, with both actors bringing real gravity to their respective roles.
- The show’s central concept — merging an old folktale with modern identity-theft anxiety — is inventive and feels genuinely fresh rather than derivative.
- Leans into psychological horror and paranoia rather than jump scares, giving it a smarter, more unsettling tone.
- A focused, self-contained limited series format means the story isn’t stretched thin across multiple seasons.
Cons
- Early reviews describe the show as “relentlessly running in circles,” with the paranoid, repetitive structure testing some viewers’ patience.
- The constant uncertainty over who the Rat really is may frustrate viewers who prefer more concrete mystery progression episode to episode.
- Its heavy focus on tension and dread over action or fast plotting may not suit viewers wanting a more propulsive thriller.
- As with many identity-theft-driven mysteries, the central premise requires some suspension of disbelief around how completely someone’s identity can be hijacked.
Similar Shows
- The 8 Show — Ryu Jun-yeol’s prior major Netflix Korean series, for more of his range in high-tension survival/mystery storytelling.
- Mantis and Kill Boksoon — for more of Sul Kyung-gu’s recent Netflix Korean thriller work.
- Squid Game — for another Netflix Korean series exploring how desperation and modern systems strip away personal identity.
- Revelations (2025) — another Korean mystery thriller adapted from a webtoon, for a tonally similar recent Netflix Korean original.
- Money Heist: Korea — for more high-stakes Korean thriller storytelling centered on deception and hidden identities.
Final Verdict
Mousetrap takes a genuinely clever premise — an old Korean folktale reimagined as modern identity-theft horror — and elevates it with two of Korea’s most respected actors sharing the screen for the first time. While early reviews suggest its relentless, circling mystery structure may test some viewers’ patience, the show’s thematic ambition and central pairing make it one of the more intriguing Korean thriller releases of the year.
Rating: 7/10 — A stylish, thought-provoking identity thriller that occasionally sacrifices momentum for atmosphere, but delivers a genuinely fresh premise.
FAQs
When does Mousetrap release? August 28, 2026, exclusively on Netflix.
How many episodes does Mousetrap have? 10 episodes.
Who stars in Mousetrap? Ryu Jun-yeol as Moon-jae and Sul Kyung-gu as No-ja lead the cast, alongside Lee Kyu-hyung.
What is Mousetrap based on? It’s adapted from the Kakao webtoon Field Mouse by Ludovico, itself inspired by a traditional Korean folktale about a rat that steals a person’s identity by eating their fingernail clippings.
Is Mousetrap a horror series? It leans into psychological horror and paranoia around identity theft and technology, rather than supernatural horror or traditional jump-scare horror.
What was Mousetrap’s original title? It was previously known as The Rat during development before its official English title was confirmed.
Why does No-ja agree to help Moon-jae? It’s complicated — No-ja isn’t a purely altruistic ally. He’s actually been hunting Moon-jae for three years over an unpaid debt, so his initial motivation for getting involved is financial, not selfless, giving their partnership real tension from the start.
What does the folktale that inspired Mousetrap actually involve? In the traditional Korean tale, a field rat eats a person’s discarded fingernail clippings and transforms into an exact physical duplicate of that person, eventually replacing them entirely. The show reimagines this literally supernatural transformation as modern identity theft via stolen digital and biometric data.
No, it’s a standalone limited series, not connected to any existing franchise or shared universe.
Where can I watch Mousetrap? It’s a Netflix Original, available exclusively on the platform.
Is Mousetrap connected to any other Korean dramas? No, it’s a standalone limited series, not connected to any existing franchise or shared universe.