Mousetrap (들쥐) on Netflix: Cast, Plot, and Why Everyone’s Talking About It Before Its Aug 28 Premiere

A reclusive novelist who hasn’t left his apartment in years is a strange enough hook. A reclusive novelist who wakes up to find someone else has taken over his fingerprints, his passwords, and his identity is the kind of premise that gets a press conference trending before a single episode airs.

Reading through the cast press conference coverage and Netflix’s own rollout for Mousetrap, this is shaping up to be one of the more distinct thriller premises Netflix Korea has put out this year — less a whodunit, more a who-even-am-I-anymore.

Fast Facts First

• What Is Mousetrap Actually About?
• Who’s in the Cast of Mousetrap?
• Why Is Mousetrap Generating Buzz Before It Even Premieres?
• Where and When Can You Watch Mousetrap?
• How Does Mousetrap Compare to Other Recent K-Drama Thrillers?

What Is Mousetrap Actually About?

Mousetrap follows Moon-jae, a reclusive novelist whose identity is stolen overnight by a mysterious figure known only as “the Rat.” His fingerprint stops unlocking his own phone. His passwords fail. His name stops being his.

When I checked Netflix’s own rollout description, the premise draws on a Korean folktale in which a rat that eats a person’s fingernail clippings can take on that person’s form and life — the kind of local myth that translates surprisingly well into a modern identity-theft thriller.

Stripped of his money, his name, and any proof of who he is, Moon-jae ends up teaming with a loan shark and a detective to track down the Rat. It’s based on the webtoon Field Mouse, and runs 10 episodes at roughly 50 minutes each.

In the original folktale, the rat isn’t a metaphor for anxiety or paranoia — it’s a literal creature that studies a person closely enough, down to the fingernail clippings they’ve thrown away, to become an exact double. Mousetrap keeps that unsettling literalism instead of softening it into a more conventional impostor thriller, which is part of why the premise stands out even before a trailer breakdown exists.

That folklore root also explains why the marketing keeps circling back to identity documents and biometric details — fingerprints, passwords, the small bureaucratic proofs of who you are — rather than leaning on a more generic stalker or doppelganger setup.

Who’s in the Cast of Mousetrap?

Ryu Jun-yeol takes on a rare dual role here, playing both Moon-jae and, per the show’s own marketing, an antagonist side of the identity-theft premise — a meatier assignment than his more straightforward leading-man roles in the past.

Sul Kyung-gu plays No-ja, the loan shark who becomes Moon-jae’s unlikely ally, and Lee Kyoo-hyung plays Sun-yong, the detective rounding out the trio hunting the Rat.

Reading the director’s press-conference comments closely, I found that Kim Hong-sun — who previously directed Dear Hongrang and Money Heist: Korea – Joint Economic Area — is behind the camera, which tracks with the tense, twist-driven tone Netflix’s rollout is leaning into.

Why Is Mousetrap Generating Buzz Before It Even Premieres?

The cast and director held a press conference in Seoul on August 20, 2026, and that event — not a Netflix Top 10 placement — is what’s driving the current wave of coverage.

You’ll probably notice a pattern with Netflix Korea’s bigger swings: press-conference buzz for a distinctive premise tends to spike interest before premiere, then either pays off or doesn’t once the show is actually watchable. Mousetrap’s premise — an identity theft thriller rooted in Korean folklore — is unusual enough that it’s earning attention on concept alone.

Honestly, that’s a smaller and more honest hook than most trend pieces get to use. There’s no chart ranking to point to yet. What’s real right now is a confirmed cast, a confirmed director, and a confirmed premiere date — everything else is still ahead of it.

Kim Hong-sun’s track record is doing some of the heavy lifting for expectations here. Dear Hongrang built a reputation for slow-burn, twist-heavy melodrama, and Money Heist: Korea – Joint Economic Area showed he can handle a large ensemble cast without losing the thread of a central mystery — both skills the Mousetrap premise leans on directly.

Where and When Can You Watch Mousetrap?

Mousetrap premieres globally on Netflix on August 28, 2026, as a Netflix-exclusive series — there’s no separate Korean broadcast network involved.

All 10 episodes are expected to land at once, following Netflix’s standard drop pattern for its Korean original thrillers, rather than a weekly release schedule.

Watching while you travel? Streaming over hotel or airport Wi-Fi is where a VPN like NordVPN earns its keep — it keeps the session private on shared networks and helps you keep your usual setup on the road.

Disclosure: this post contains an affiliate link — if you buy through it, we may earn a commission at no extra cost to you.

📌 Related reading: if you want a running list of what’s actually topping the charts once new releases land, see 5 Korean Dramas Ruling Netflix’s Global Chart Right Now (July 2026) for the format this site uses to track it.

How Does Mousetrap Compare to Other Recent K-Drama Thrillers?

Mousetrap’s identity-theft hook sets it apart from the revenge-and-justice angle of recent hits, even though all three lean on a strong ensemble cast and a twist-driven structure.

✅ Quick gut-check: if you liked the ensemble-chase energy of A Shop for Killers but want something built around a mystery of self rather than a mission, Mousetrap’s premise is aimed squarely at that gap.

What to Know Before You Hit Play

• ✅ It’s a 10-episode series, all expected at once — plan for a binge, not a weekly watch.
• ✅ Ryu Jun-yeol plays a dual role, so pay close attention early on to which “side” of the identity swap a scene is following.
• ✅ The premise is inspired by Korean folklore, not a straight remake of an existing IP — don’t expect a 1:1 match to the source webtoon’s every beat.
• ✅ No chart ranking exists yet as of this writing — treat any “definitely a hit” claim you see elsewhere as speculation until it airs.

Where Pre-Premiere Coverage Gets Ahead of Itself

The biggest one: treating press-conference buzz as proof of a hit. A well-attended press conference means marketing worked, not that the show has landed with viewers yet.

The second: confusing the webtoon source material’s plot beats with the show’s actual episode-by-episode structure, which Netflix hasn’t detailed scene-by-scene ahead of premiere.

The third: assuming Ryu Jun-yeol’s dual role means a literal split-screen gimmick throughout — the marketing language points to a meatier, more layered performance rather than a visual trick.

FAQ

When does Mousetrap premiere on Netflix?

Mousetrap premieres globally on Netflix on August 28, 2026, as a Netflix-exclusive series with all episodes expected to release at once.

Who plays the lead role in Mousetrap?

Ryu Jun-yeol plays Moon-jae, the novelist whose identity is stolen, in what the show’s marketing describes as a rare dual role. Sul Kyung-gu and Lee Kyoo-hyung round out the main cast.

Is Mousetrap based on a true story or existing series?

No. It’s based on the webtoon Field Mouse and draws on a Korean folktale about a rat that can take on a person’s identity after eating their fingernail clippings, not on real events.

Sources

• Netflix: Mousetrap Premieres August 28
• The Korea Times: Mousetrap Turns Korean Folktale Into Netflix Thriller

Fact-checked based on public sources as of August 23, 2026.