Mannix is hired by successful heart surgeon Cameron McKenzie, whose young son was apparently kidnapped by someone who looked exactly like the doctor, driving a car that also looked exactly like the doctor's car. Mannix agrees to look into the kidnapping if the police will be notified once Mannix runs into a dead end. But then Dr. McKenzie confesses something he has held back: the kidnappers don't want a ransom -- they want McKenzie to let one of his patients die in exchange for the boy's life.
—aldanoli