Shutter Island - Plot revealed - Spoilers!

Shutter Island pulls a Memento-style trick. Or Fight Club. Or any other 'twist' movie where the protagonist is slightly crazy and happens to be the very person he's hunting for. Former US Marshal Teddy (played by Leonardo DiCaprio in the movie) killed his wife after finding out she'd gone crazy and killed their three young children. So he's sent to Shutter Island and happens to be patient 76. What a tweest!