This is a different type of thriller than I'm used to. More of a mystery with a hint of horror at the end.
The story is given to us via blog posts written years after the horrifying events happen. They are told by a young, brilliant psychiatrist named Parker who had just started a job at a rundown, dreary asylum. He explains his ideals as genuinely wanting to help people. His mother was a paranoid schizophrenic who ended up committing suicide when he was a young boy.
There is a patient at his asylum who no one interacts with. They call him Joe. Joe has been in the asylum since he was 6 years old and is what they call incurable. Doctors, nurses and other patients tend to kill themselves after being around Joe. He is the ultimate puzzle and Parker sets his mind to solving Joe's case.
Joe is not what Parker expected. Joe is much, much worse.