There’s an old Korean folktale about a field mouse that eats a person’s clipped fingernails and, in doing so, transforms into an exact copy of them — taking over their life, their identity, everything. It’s a strange, eerie bit of folklore, and it turns out to be the perfect foundation for a psychological thriller. Netflix just confirmed that Mousetrap, its new mystery series built around exactly that premise, will premiere globally on August 28, and the newly released teaser trailer and poster make it clear this one is going to mess with your head.
Mousetrap Netflix’s Korean Series Trailer Out: What the Trailer Actually Shows
The story centers on Moon-jae, a reclusive novelist who writes under a pen name and hasn’t left his house in years, living out the same quiet, isolated routine day after day. Then things start breaking in ways that shouldn’t be possible. His fingerprint stops unlocking his own phone. His passwords quit working. One by one, every piece of proof tying him to his own identity slips out of his hands, until he’s left with no money, no name, and no real way to prove he’s actually himself.
Stripped of everything, Moon-jae is forced back out into a world he’s spent years avoiding, chasing down a mysterious figure who calls himself “The Rat” — someone who seems to understand exactly who Moon-jae is, even as Moon-jae himself is losing the ability to prove it.
The trailer’s tagline lands with real weight: “Prove I’m real, or I’m the imposter.” It’s a tidy summary of the psychological trap the whole series seems built around — a story less about solving a mystery and more about a man forced to fight for ownership of his own existence.
The Poster Hints at Something Even Stranger
Alongside the trailer, Netflix also released the show’s first poster, and it does a lot of quiet work on its own. Moon-jae, played by Ryu Jun-yeol, stares off into the distance with a hard, unsettled expression. Next to him, there’s another face layered in alongside the silhouette of a rat — a visual choice that leans directly into the show’s central tension between what’s real and what’s been faked. The poster’s tagline reinforces the same idea running through the trailer: if you can’t prove who you are, you become a fake.
Who’s Involved
Mousetrap comes from director Kim Hong-sun, whose genre credits include Dear Hongrang and the Korean adaptation of Money Heist, working from a screenplay by Lee Jae-gon. The series is adapted from the webtoon Field Mouse, which itself draws from the folktale mentioned above.
Ryu Jun-yeol, known for Revelations and The 8 Show, leads the cast as Moon-jae. Sul Kyung-gu, who’s appeared in Good News and Kill Boksoon, plays Noja, a loan shark who ends up tangled up in Moon-jae’s search — whether as help or complication isn’t entirely clear yet. At one point in the trailer, Noja tells Moon-jae, in so many words, that this is a game where the whole point is finding yourself, which only deepens the sense that nothing in this story is going to be straightforward. Rounding out the main cast is Lee Kyoo-hyung, from Prison Playbook and Hi Bye, Mama!, playing Sun-yong, a detective who’s independently chasing down the same figure known as The Rat.
Why This One’s Worth Keeping an Eye On
Identity-theft thrillers aren’t new, but building one around a genuinely unsettling piece of folklore — rather than hacking, fraud, or the usual conspiracy-thriller mechanics — gives Mousetrap a distinct enough hook to stand out. Kim Hong-sun has a track record with genre storytelling that leans into atmosphere and tension rather than pure spectacle, which suggests this could lean more toward slow-burn psychological dread than a flashy action-thriller.
Mousetrap premieres globally on Netflix on August 28.