Lady Vengeance is the third in a trilogy of films about revenge set in Korea by the great and very controversial director Park Chan Wook. The first was Sympathy for Mister Vengeance (2002) and the second OldBoy (2003). It has been hailed as one of the best in cinema noir, or what is known in Asia as "Extreme".
That is because it deals with an English teacher, Mr Baek (acted by Choi Min-sik who starred in OldBoy), a trusted and revered member of the species, who secretly is a serial killer who kidnaps, tapes and then murders children for their ransom money. His motivation is to "to buy a yacht".