1894: It's the beginning of the end for H. H. Holmes. After more than a decade committing a swath of crimes from Texas to Toronto, investigators are hot on the trail of the most daring and eccentric criminal of the age. What began as a man wanted for conspiracy to commit fraud turns into an extensive investigation that would reveal unspeakable horrors.

Detective Frank Geyer of Philadelphia is assigned his most bizarre and dramatic case to date, where he'll exhaust an entire summer searching for three missing children. All the while, in Chicago, exploration into Holmes' World's Fair Hotel grips a nation. The press dub it the "Murder Castle."

Witness the very real investigation and sensational trial that put a stop to the century's most ruthless killer. A man born and bred in rural New Hampshire, who evolved into one of the most unique violators of law in American history. A handsome charmer skillfully making a place for himself among polite society while hiding an ugly secret.

This is the unmasking of Henry Howard Holmes.