Israel Keyes was a predator who struck all over the United States. He would break into a stranger's house, abduct his victims in broad daylight, and kill and dispose of them in mere hours. And then he would return home to Alaska, resuming life as a quiet, reliable construction worker devoted to his only daughter. When journalist Maureen Callahan first heard about Keyes in 2012, she was captivated by how a killer of this magnitude could go undetected by law enforcement for over a decade. And so began a project that consumed her for the next several years --- uncovering the true story behind how the FBI ultimately caught Israel Keyes, and trying to understand what it means for a killer like Keyes to exist.