McCall, a man with a mysterious past, tries to begin a new life in Boston. He walks past a Russian gang beating a girl on the street and tries to save her, but fails. The girl, Teri, escapes, but McCall is shakened and feels that he must protect her. McCall seeks Teri out and discovers that she is being held captive by the Russian gangsters who brutalize her both physically and emotionally. McCall realizes that he has special skills at his disposal and decides to take action and rescue Teri. He seeks revenge against her captors and helps Teri recover both physically and emotionally by providing her with the resources to get a fresh start in life. The film is a thrilling journey of a man who revisits his old, violent ways to empower the weak and fight for justice.