On a Beam of Light

K-PAX introduced readers to a young man named "prot," a mysterious patient at a mental hospital who claims to be from the planet K-PAX. Prot is assigned to psychiatrist Gene Brewer, who is determined to prove that the stranger is nothing more than a tragic victim of multiple personality disorder. The doctor gradually begins to realize that prot is having a remarkable effect on the mental health of the hospital's other patients, and finds himself doubting his own diagnosis as prot begins to show signs that he is much more than he appears.
In On a Beam of Light, prot returns and his sessions with Dr. Brewer continue with astonishing results. Through the use of hypnosis, more is painstakingly revealed about the traumatic background of the patient whose real name is Robert Porter. Prot, meanwhile, creates a nationwide stir in a televised talk-show appearance. When he claims to be returning to K-PAX for good, his doctor finds himself in a race against time as he digs ever deeper to find the key to unlock this man's psyche before he is reduced to a shattered, lifeless shell.