Lady Vengeance
(2005)
An elaborate Korean revenge drama from the Director of Oldboy

Geum-Ja (Yeong-ae Lee) is framed for a child murder by the child killer.

Geum-Ja plots revenge during her 13 and 1/2 year prison sentence.

After being released, she uses her prison buddies to locate and abduct the child killer. She then discovers that he killed another 3 children.

She presents the evidence to the families of the victims, and they all participate in the child killers grisly execution.

Thanks Don P!