1930s Korea, in the period of Japanese occupation, a new girl, Sook-hee, is hired as a handmaiden to a Japanese heiress, Hideko, who lives a secluded life on a large countryside estate with her domineering Uncle Kouzuki. But the maid has a secret. She is a pickpocket recruited by a swindler posing as a Japanese Count to help him seduce the Lady to steal her fortune.

A girl wakes up in a huge secret laboratory, then accidentally meets another girl who is trying to protect her house from a gang. The mystery girl overthrows the gang with her unexpected powers, and laboratory staff set out to find her.

Ja-yoon is a high school student who struggles with memory loss after she endured some unknown trauma during her childhood. While trying to uncover the truth, she is unwittingly dragged into a world of crime and finds herself on a journey that will awaken many secrets hidden deep within.

A South Korean woman in her sixties enrolls in a poetry class as she grapples with her faltering memory and her grandson's appalling wrongdoing.

Shot in Busan, Shadow Island is the name of a location as well as the main character’s name. The film explains the legacy of violence passed down through three generations. The lives of a murderous father, a son addicted to violence, and the victims of violence intertwine into a surprising finale. As the film shifts through the past and present, it reveals a painful family history that eats away the soul and leads to a burdened fate of self-destruction.