U.S. Marshal Edward Daniels (DiCaprio) and his partner Chuck are investigating a hospital for the criminally insane at Shutter Island. It is fortress-like, because they house the "worst of the worst" offenders, whom are believed to be incurable. Dr. Cawley (Kingsley) tries various types of therapy to bring them back without resorting to more extreme treatments. (This takes place around 1952, so he is trying to avoid lobotomies). They are looking for an escaped inmate named Rachel who drowned her 3 children. She is initially the primary focus of the investigation.
I liked the way the story was told. It is important to remember that not everything is as it seems. Look for a BIG turn toward the end which explains what is happening.
Content warnings: a few scenes with blood and a some with bad language.