Dr. Rex Martin is a top neurosurgeon, who is active in studying brain malfunctions that cause mental illnesses.

After Rex takes over, Berkovitch accidentally knocks over Philip Montag's brain, a parietal paralysis patient.

High school friend Jim Reston, a successful businessman at Eunice, shows up at Rex's office.

He requires Martin's aid in reaching the mind of John Halsey, a former genius mathematician who once worked for the company and is now a paranoid psychotic at a nearby asylum.

During the surgery, we see through Halsey's eyes what each stimulation changes, altering not only the location, sounds, and people involved while still allowing him to communicate through the psychosis.

In the end, it is revealed that Martin died from the injuries sustained in the car wreck and is now a sentient brain in a jar.