Thriller about a cop's search for a serial killer who leaves equations carved into his victims' skin. Despite feeling jaded and worn down by years of gangland brutality, veteran detective Eddie Argo (Stellan Skarsgard) is proud that he's always managed to play by the rules. However, circumstances begin to change as he and his new rookie partner, Helen Westcott (Melissa George), find themselves caught up in a string of horrifying murders. The victims are all members of a notoriously vicious gang, and the case forces Argo to revisit events he would rather forget. As the terror mounts, the killer stays concentrated on his ultimate goals - to make Argo pay for his past mistakes, and force him to answer the toughest of questions: would you kill the one you love to save yourself from death?