Mad Detective is a 2007 Hong Kong action film produced and directed by Johnnie To and Wai Ka-Fai. Mad Detective was first screened at the 64th Venice International Film Festival, and later premiered at the 2007 Toronto International Film Festival, before being released in Hong Kong on 29 November 2007. The film's screenplay won "Best Screenplay" awards at various Asian film ceremonies.

Plot

Chan Kwai-Bun (Sean Lau) is a brilliant detective with a supernatural gift: seeing a person's "inner personalities" or hidden ghosts. However, he is forced into retirement after severing his ear and presenting it to his retiring boss.