A mental patient is undergoing brain surgery by an alternate universe soldier named Thomas Jerome Newton. While undergoing the surgery, Newton and his team are discovered and flee the mental hospital immediately leaving the patient with exposed brain.
The Fringe team comes in and learns that before this apparent surgery, the patient was insane, but has become completely sane. After doing some research, the team finds out that this has happened a few other times at different mental facilities and also to WALTER BISHOP!!
The team comes to understand that all the patients had a piece of brain tissue removed -- pieces of tissue that belong to Walter, but the team has discovered this too late. Walter is drugged and taken by Newton to his old home where Newton inserts the brain tissue back in Walter to help him remember important information that Newton is after.
After asking Walter a series a questions, Newton takes off leaving a dying Walter. Olivia catches Newton, but she is left with two choices: She arrests Newton and gets answers to all her questions, or she lets Newton go free and in return he will tell her what to do to save Walter's life. Olivia lets Newton go free and runs back to save Walter right in the nick of time.