There’s always something to be said for a film that can lead you down one road, making you expect a certain type of film before pulling the rug out from under you and revealing something even more complex. Han Gong-ju is one such film, a quietly powerful and deeply affecting South Korean drama.

Based on an infamous true story that made huge headlines in native country in 2004, the film follows the eponymous character, a seemingly normal teen with all the awkwardness that entails. She’s pretty and instantly amiable but nevertheless has trouble fitting in when she is suddenly separated from her parents and moved to a new school. She has to deal with her new life, living with and working for the mother of a former teacher who is practically a stranger, as well as trying to hide the shocking truth about her past as her new classmates try their best to encourage her friendship and her newly discovered singing talents.

As I said, you start off the film by thinking it’s one thing but slowly, or rather repeatedly, the layers are peeled away. Did she commit a crime, perhaps steal something or accidentally cause a death? The film expertly masks the truth from the outset but cleverly uses flashbacks at key moments to expose what really happened and it becomes increasingly shocking and tragic the more we find out. It’s something of a cinematic puzzle but one that becomes less and less appealing to try and work it out because, just like its meek protagonist, it’s too horrific to contemplate especially when we’re dealing with such a likeable character for whom we only want the best.

Along the complex and progressively tragic narrative, the film also tackles relatable themes for anyone who didn’t find high school a walk in the park (which is probably most people). These include issues of judgement, acceptance, friendship, fulfilling one’s potential and trying your best to escape your past even as it clings onto every fibre of your being. Director Lee Su-jin, making a mightily impressive debut, deftly and meaningfully explores these and other themes without it ever feeling like it’s banging you over the head.

On top of its nuanced yet powerful handling of the story, the whole thing is bolstered even further by some fantastic performances. Relative newcomer Chun Woo-hee is exceptional in the lead role, capturing all the tortured emotions of a girl trying her best to escape her past, both alienated by her new surroundings and using it as a springboard to move on. Lee Young-Lan brings a warmth to the initially hard-nosed and even mean spirited grocer who takes in Gong-ju despite her efforts to find love and settle down with someone again in her later years. The film even manages to shed a refreshing new light on the high school scenes, particularly when it comes to the group of girls – headed by Eun-Hee (Jeong In-seon) – who try their best to welcome Gong-ju and encourage her evident vocal talent even as she protests.

And why exactly Gong-ju protests is the crux of the mystery surrounding what happened to her before her arrival and from there the truth slowly begins to spiral out into the open. I won’t reveal what that truth is here but needless to say it delivers several gut punch moments of emotion that takes the film from an intriguing character piece into a supremely effective drama about how the past can not only stay with you but shape who you are, for better or worse.