John Snow, an inventor with a rare brain disease, is found shot to death in an alley beside the Massachusetts General Hospital an hour before he is scheduled to undergo an experimental operation to correct the problem. The scene looks like suicide, but the Boston police cannot rule out homicide. They call in Dr. Frank Clevenger, a forensic psychiatrist, to aid in the investigation. Clevenger learns from Snow's neurosurgeon, who was also the pioneer of the scheduled operation, that one of the side effects, if the operation had been successful, would destrbe the obliteration of the patient's emotional ties to his past. Snow had accepted, perhaps even desired, this outcome. The surgeon seems distraught at losing his opportunity to perform the operation for the first time. He takes to dropping in on Clevenger at his home to talk about his disappointment. Clevenger's adopted son, Billy, becomes the subject of his attention and flattery. Although the troubled Billy seems much more mature and well-adjusted than in previous books, he soon develops a case of hero-worship on the surgeon and decides that he wants to become a neurosurgeon as well. Clevinger feels jealous and threatened by this relationship. Snow had a wife, a son, and a mistress. Had the operation been a success he would have walked away from all of themand begun a new life. Several days after his death his mistress is found with her throat and wrists slashed. Again it is unclear whether the death is suicide or murder. Snow's wife claims to have known about and accepted her husband's affair, but Clevenger finds her forebearance the more surprising when he discovers a portrait of Snow's lover hanging in their living room. Snow's teen-age son hates him. Snow and his partner have had friction over Snow's inventions. The husband of Snow's lover has recently been tipped off about the love affair and is an angry and aggressive man. Clevenger discovers that both Snow's partner and his son were seen close to the scene of his death at about the time it occurred. Clevenger calls everyone into the room at the end and tricks a confession from the guilty party.