In 1995, a beloved mother is found raped and murdered in the accounting office where she works. The bloody body of her young daughter is nearby. But as police photograph the scene, they get the shock of their careers.

When Lovetta Armistead, a beautiful and hardworking single mother in Oak Cliff, Texas, marries a new man, Gary Green, she has no idea the monster she's brought into her home.

In 2003, a young man in Georgia shoots his father in the head sixteen times. Days later, the body of a nun is found on the side of a Virginia road. The story behind these two crimes haunts those involved to this day.

In 2003 in Burlington, North Carolina, pregnant April Greer vanishes. Her boyfriend says she left him, and her family is worried sick. No one knows that the unbearable truth about what really happened to April is the stuff of nightmares.

For two years, in Dallas, Texas, surgical patients fall victim to Christopher Duntsch, a monster with a scalpel and a medical degree. Dallas Assistant District Attorney Michelle Shughart isn't sure what to think when she is first approached with the case. Is this medical malpractice? Or an evil man with a scalpel?

In 2011, Mother's Day in Tustin, California, looks a little different this year for high school freshman Tony Gana. His mother, Annamaria Gana, is battling stage 2 breast cancer. She says she's fine, but Tony can tell the medicine and the chemo is taking its toll. Officer Todd Hylton is called to the scene of an alleged shooting. Just moments earlier, the caller told dispatch that his mom shot him

In 1980, in Radford, Virginia, college freshman Gina Hall goes out dancing and never returns. Police follow her trail to a mysterious lake house, but where she goes from there is a mystery that has endured for 40 years.

In 2000, in South Barrington, Illinois, a rookie cop responds to the scene of what many believe to be the site of an accidental drowning. But for that cop, something about it doesn't sit quite right. It's a hunch that, 10 years later, he still hasn't forgotten.