Bundy, Gacy Dahmer, The Green River Killer, and BTK. What made these monsters tick? And finally, how did America's most famous serial killers change the face of how crime is investigated today? In this series, we will explore these questions by doing something that's never been done -- examining all five killers at once, interweaving their timelines to show their surprising similarities and differences. With access to exclusive interviews with survivors, investigators, forensic psychologists, prosecutors and family members, as well exclusive access to never-before-seen/heard materials. We'll explore the formative years of these killers in order learn about their motives; and we'll contextualize the period in which they operated, anchoring it in the surprising elements of society, technology, crime solving that actually contributed to their ability to perfect their disturbing approaches to murder.