Overview: Scheming killers. Liars and con artists who deceive their families, their friends and the public. They use their intelligence to get away with murder. What drives these manipulating minds and who is most evil? Dr. Michael Stone is evaluating the cases of individuals who have planned and schemed to commit heinous crimes. Diane Downs blames a hitchhiker for shooting her children, but a surviving daughter says her mother pulled the trigger. Michael Swango was a brilliant doctor with a dark fascination. He is suspected of killing up to 60 patients. John Robinson fooled his family and community into thinking he was an upstanding citizen and entrepreneur. In reality, he was profiting from the deaths of vulnerable women. Dr. Stone then travels to Georgia to interview Martha Ann Johnson, who was convicted of killing her daughter in an attempt to get her husband back. How do schemers fool the people around them and what makes them different from other killers?