Boston is filled with saints and sinners. More than cobblestones and ivy, this historical melting pot has bred both mythical monsters and notorious mafia bosses. To understand how one of the FBI's Most Wanted was able to rule Boston - and evade the FBI - for decades, Marcus goes on the air with famed radio host Howie Carr before donning a disguise to attempt his own vanishing act inside Quincy Market. Then, Marcus sits down with noted Harvard professor, Dr. David Bernstein, to get inside the head of psychopath Albert DeSalvo, who went down in history as The Boston Strangler. But the DNA evidence revealed by forensic scientist James Starrs throws the true identity of the Strangler into question.