Nightmarish folktale becomes Netflix Korea thriller 'Mousetrap'

A popular Korean folktale that warns children about the dangers of carelessly discarding fingernail clippings is the subject of a new Netflix Korea series starring Ryu Jun-yeol.

According to the unsettling story, if a mouse eats a person’s discarded nail clippings, it can transform into an exact replica of that person.

The new series, “Mousetrap,” takes the folklore at face value, imagining a far more nightmarish scenario in which a man’s life is thrown into chaos after a mouse consumes his nail clippings and assumes his identity.

Ryu stars as the unfortunate Moon-jae, a reclusive writer whose life is upended when a mysterious double emerges and begins impersonating him, wreaking havoc on his life — and particularly his finances.

Speaking at a press conference in Seoul on Thursday, Ryu said the series, based on both the folktale and the popular webtoon “The Rat Trap,” goes beyond its fantastical premise to explore deeper questions about identity and what it means to be oneself.

“Looking at the original webtoon, I felt that the writer was not simply telling a story for the sake of entertainment or excitement, but had a very distinct philosophy and used the story to explore some profound ideas,” Ryu said.

“So when I focused on what the story was really trying to say, I found myself thinking about questions such as how we prove and define who we are, whether the person we define as ‘me’ is truly who we are, and whether the person we see as someone else is really that person. I think I put a lot of effort into expressing those ideas in a way that would be easier for viewers to understand,” he said.

The series rests heavily on Ryu’s dual performance as Moon-jae, the man whose identity is stolen, and Mouse, the creature who assumes his identity. Discussing the challenge of playing two characters who are physically identical but fundamentally different, Ryu said he and the team focused on subtle distinctions rather than relying on overt transformations.

“I spent a lot of time discussing it with the director,” he said. “I talked about something similar when I did the film ‘The Night Owl.’ Back then, we had to figure out how to convince the audience that the character was visually impaired when everyone knew that I wasn’t actually visually impaired. We faced a similar challenge this time, and rather than forcing things or overplaying them, we tried to build the character by focusing on subtle details, such as his personality and facial expressions.”

“We also created moments in the scenes where the characters communicate with each other through their voices (in ways) that would surprise viewers. They’re not exactly Easter eggs, but I’m confident there will be some fun details for viewers who watch closely,” he added.

On screen, Ryu is joined by veteran actor Sul Kyung-gu, one of the most commanding screen presences in Korean cinema, whose 30-year career includes classics such as “Silmido” and “The Merciless.”

Sul plays No-ja, a loan shark determined to collect a long-overdue debt from Moon-jae.

“As Ryu said, there are no heroes or supernatural beings with extraordinary powers in our series,” Sul said. “The characters may seem somewhat empty or lacking in certain ways, but it’s interesting to see how they are the ones who ultimately drive the story forward. It’s a story that keeps you guessing and searching for the truth, and I found it incredibly immersive.”

“Mousetrap” premieres on Netflix on Aug. 28.