Her character Han Yeo Reum was adorably selfish and spontaneous in the romantic comedy "Discovery of Love," but in her new film role actress Jung Yoo Mi is desperately determined.

In the film "Manhole," the actress plays a character that is desperate to find her younger sister before a serial killer ends her life.

Despite the grim plot, playing the role of Yeon Soo in "Manhole" was an easy decision. Jung Yu Mi has always wanted to be in a thriller. She has long been a fan of thrillers and she has been eager to try a different kind of role.

"Honestly, when they told me that it would be a thriller, I just took it," said Jung Yu Mi.

And playing a character that was driven and desperate also came naturally. She just thought about how she would react in the same situation.

"I just acted with the idea of having to find my younger sister," she said at a press conference for the film.

"Manhole" concerns a serial killer whose murders have terrified the residents of the Shinseon-dong neighborhood in Seoul. During the span of six months, ten people have disappeared in the same neighborhood. What no one knows is that the killer traps his victims using a manhole cover and then takes them via underground tunnels to hishiding place.

When Yeon Soo's 14-year-old mute sister disappears, she must find her while there is still a chance that she might be alive. Kim Sae Ron, 14, who appeared in the films "The Man From Nowhere" and "Girl At My Door," plays her sister Soo Jung.

Jung Yu Mi, 31, complimented the young star on her acting in the film.

"She's much younger than I am but I liked the fact that she has her own energy and confidence," said Jung.

Jung Kyung Ho, who appeared in the drama "Cruel City" and the films "Roller Coaster" and "Fasten Your Seatbelt," plays the serial killer Soo Chul. Having lost his family to a fire, the killer brings his victims to the underground tunnels that he lives in.

Jo Dal Hwan plays Pil Gyu, a detective who is on suspension. He is also hunting for the killer.

Jun Yu Mi's previous films include "Tough as Iron" with co-star Yoo Ah In and "Silenced" with Gong Yoo. She also appeared in "I Need Romance 2012."

Shin Jae Young is the writer and director of "Manhole."