Based on the horrific true story of Dr. H. H. Holmes, widely considered to be America’s first serial killer (and whose crimes are chronicled in the best-selling book The Devil in the White City), this eerie Halloween adventure takes visitors back to 1895 Chicago, when Holmes was kidnapping, torturing and killing victims while masquerading as a doctor and caring husband. The sprawling house that police discovered to be the scene of his ghastly crimes came to be known as the Murder Castle, and was filled with secret passages, vats of acid for disposing of the dismembered bodies and other horrors. Screams in the Park puts you right back at the scene of the crime, where the Dexter-like Dr. Holmes just may be lurking anew.

Free tickets can be purchased today only, although the dates available are this Friday, Saturday and Sunday.  Unlike Groupon or livingsocial, these freebies do not last more than the day shown (don’t how i know).