Harry Benson, a man at least 30 years old, suffers from psychomotor epilepsy. He often has seizures followed by blackouts, and then wakes up hours later with no knowledge of what he has done. During one of his seizures he severely beats two people. He is a prime candidate for an operation to implant electrodes and microcomputer in his brain to control the seizures. Surgeons John Ellis and Robert Morris are to perform the surgery, which is unprecedented for the time. In modern medicine, such a device would be called a brain pacemaker. Even though Harry is psychotic (he adamantly believes that there is no difference between man and machine) and it wouldn't necessarily stop the crimes he commits during blackouts, the doctors go through with the procedure anyway. Unfortunately, it turns out that they programmed the electrodes incorrectly, because Harry likes the shocks the electrodes give him, and he deliberately tries himself into seizures just to get the buzz. That, and he escapes without even getting any thorazine. Now, they must catch him before someone really gets hurt.
This book provides examples of:
- The Cuckoolander Was Right: Harry Benson adamantly believes that there is no difference between man and machine. He's supposed to be psychotic, and a lot of the characters think that it's just nonsense. But as the story goes on, a number of characters find themselves wondering if maybe Harry did have a point after all, as evidence of mankind's increasing reliance on the artificial and mechanical piles up before them.
- Downer Ending: Harry Benson ends up dead. Not only that, but it's strongly implied that there will be consequences for the people responsible for Harry's procedure, that include being fired or losing a house.
- Punny Name: As the result of the operation, Benson becomes a terminal for the pacemaker computer. As the final consequence of that, he becomes terminal in the medical sense.
- The Shrink: This is Dr. Janet Ross's job. She is trying to help Harry Benson, and feels that everyone else is being so insensitive towards him. However, she is quite aware that he is dangerous.