Want to know why the “Shutter Island” plot is so controversial? Want to know why fans of the Martin Scorsese-directed drama remake still have fans talking about the ending? Then read on, because this was a movie that took a simple mystery and turned into a spine-tingling with a twist ending that has had fans debating about it ever since. If you haven’t seen it, then there are five major points that can get you through a discussion about the plot of “Shutter Island” (Warning: spoilers ahead).

The basic storyline. The premise of “Shutter Island” is that two U.S. Marshalls, veteran Teddy Daniels (played by Leonardo DiCaprio) and newbie Chuck Aule (played by Mark Ruffalo), have been called to the island to investigate the disappearance of an inmate at a mental institute for the criminally insane. The federal institute should have no means of escape, so the two officers are convinced that Rachel, the inmate, must still be on the island.

The obstacles. Teddy, who initially has a run-in with the doctors at the hospital concerning the release of some patient’s documents, tells his partner that he has another motive for requesting this case. He has an informant who said that Shutter Island’s staff has been testing using the patients as guinea pigs to test experiments drugs on with the backing of the federal government and he intends to find the proof on the island and expose those involved.

Is this real or just some drugs? Eventually, during a storm in which Teddy and Chuck find themselves trapped on Shutter Island, they go searching the grounds and discover Rachel hiding in a cave. She tells Teddy that she isn’t a patient, but rather a doctor who found out about the treatments and threatened to expose the doctors, but she was framed and injected with some of the drugs, which forced her to hallucinate. Eventually, she broke free and has been hiding in the caves ever since hoping that she can figure out a way to escape the island. Rachel then remarks that Teddy is showing signs of being drugged that he must flee Shutter Island as soon as possible before the doctors get ahold of him as well.

The truth revealed. Teddy goes hunting for the doctors (assuming they have killed Chuck, who has gone missing along with Rachel) only to discover that the doctors have been looking for him. As it turns out, Teddy is not a U.S. Marshall, but rather an inmate at the hospital named Laeddis. He was admitted after having a nervous breakdown following an incident where he discovered that his mentally disturbed wife had killed their two kids. In his grief, he killed his wife, which sent him over the edge. He was at the hospital because he had been unable to cope with the guilt and invented the Daniels persona as a way of blocking out what had happened. The doctors tell Laeddis that he has been increasingly violent and they were prepared to lobotomize him if he was unable to accept what had happened to him and what he had done.

The final question. The shocking conclusion to “Shutter Island” has Laeddis sitting with his doctor (who had masqueraded as Chuck) and talking as if he was back in his Teddy persona. The doctor fears that their experiment they tried with Laeddis has failed and that he still refuses to accept what he has done when Teddy turns to the doctor and asks if it’s better to die as a man or live as a monster. Laeddis then gets up and goes calmly with the doctors who will lobotomize him. The ending was so controversial because it makes the audience wonder if the treatment did indeed work and Laeddis was choosing the lobotomy of his own free will or if he did indeed slip back into Teddy.

-Mark Dodson