The Crucible (2011)

Cast
Gong Yoo (공유) as Kang In-ho (강인호)
Jeong Yu-mi (정유미) as Seo Yoo-jin (서유진)
Kim Hyeon-soo (김현수) as Kim Yeon-doo (김연두)
Jeong In-seo (정인서) as Jin Yoo-ri (진유리)
Baek Seung-hwan (백승환) as Jeon Min-soo (전민수)

Also known as "Dogani" and "Silenced"

Trailer

Synopsis
“The Crucible” follows a group of children with disabilities who suffer physical and sexual abuse at the hands of their teachers.
Gong is one of a few star authors in Korea whose novels have sold more than a million copies. When her novel was published in June 2009, it became an instant hit not only because it was written by Gong but because it is based on a true story.
The film begins as Gang In-ho (Gong Yoo), who is working to earn money for his daughter’s surgery, is appointed to a school for hearing-impaired children in Gwangju. But what he discovers there is an ugly truth: the children are being physically and sexually abused by their teachers. When he decides to fight for the children’s rights and expose the crimes being committed at the school, In-ho teams up with human rights activist Seo Yu-jin (Jeong Yu-mi). But he and Yu-jin soon realize the school’s principal and teachers, and even the police, prosecutors and churches in the community are actually trying to cover up the truth.