This is a corking film from Bong Joon Ho with an equally super performance from Hye-ja Kim as the "Mother". Her son "Soon Do-joon" (Won Bin) is accused of murdering a young girl. The police seem convinced of his guilt and her lawyer suggests he be detained in an hospital - rather than a prison - so she sets out, determinedly, to establish his innocence. As she takes to her task, she soon becomes obsessed, her own mental stability begins to wobble and we are drawn into a dark, almost sombre, crime thriller. It has plenty of twists and turns, and by the end (which comes pretty much from the…