Shutter Island is an American psychological thriller directed by Martin Scorsese , released in 2010. It is an adaptation of the novel Shutter Island by the writer Dennis Lehane. In the film, Teddy Daniels played by Leonardo DiCaprio, and his partner Chuck Aule played by Mark Ruffalo, arrive on the Shutter Island to investigate the escape of Rachel, an intern who drowned her three children. Very soon, the two policemen perceive the strange atmosphere of this closed place. They quickly realize that no one will help them in their mission and they ask themselves several questions: what role do the doctors who run this hospital play on the island and what methods do they experiment on their patients? What is the purpose of the lighthouse that dominates the island and whose entrance seems inaccessible? "Crazy people, they're the perfect subjects. they talk, nobody listens." This quote said by Teddy, shortly after arriving on the island, shows that he knows that something is wrong but he cannot prove it.

Convinced that the escape has benefited from accomplices, the two marshals will try to discover what is hidden from them, but a coded message left by Rachel pushes them further into the mystery. This tragedy brings back elements of Teddy's past: he knew the pain of losing his family in a fire. But when Chuck Aule discovers that the responsible for his colleague's misfortunes is interned on the island, he wonders about Teddy and ask himself the question, “did he come to investigate or to take revenge?” When the two investigators question the staff about the island's doctors and their treatment of the prisoners, Teddy Daniels seems very interested in an island prisoner named Andrew Laeddis and asks a lot of questions about him. This one accentuates Chuck Aule's idea that Teddy wants revenge.

Despite all the clues and deliberate mistakes throughout the film, we only discover the truth at the very end. We understand that two themes are part of the film from the beginning, the fire and the water. The fire represents the imaginary death of Teddy's wife. According to his memories, the fire was caused by a man named Laeddis. In the film, the fire is represented by the gunshots which appear in Teddy's WWII memories as well as in the matches, lit by Teddy or by Laeddis, and finally in the car explosion; another Teddy's memory in which his wife and daughter are standing right next to an exploding car. This makes him remember their death into a fire. The water is also everywhere in the movie: all around the island, which made it difficult for Teddy to get to the lighthouse because it was high tide, or in the storm that falls on the investigators. This could represent the truth that falls from the sky on Teddy. Finally, Rachel, the woman who disappeared, was interned for drowning her three children.

Finally, at the end of the film, we understand everything and discover that Teddy Daniels is a patient of the hospital who killed his wife after she drowned their three children. This woman is Rachel. The film is made in such a way that we don't want to believe that Teddy is really a patient of the hospital. Unfortunately, after watching the film a second time, we begin to understand that Teddy is indeed a patient of the hospital, and that all this staging is done to help him. The film ends with Teddy Daniels and Chuck Aule talking outside of the hospital, sitting on steps. After a minute of talking, Teddy asks his teammate, "What would be worse: to live like a monster, or to die like a good man?", then gets up and walks away.