Malcolm realizes the suspect in the "Junkyard Killer" case may have a connection to his father.

Jessica continues to search for more information on the "Girl in the Box," but is confronted by the "Carousel Killer," who has a very public vendetta against the Whitlys. While the NYPD investigates families tied to Martin's victims, it's ultimately up to Malcolm and Jessica to track down the tip-line caller, turned killer, who is blackmailing her. Meanwhile, Ainsley receives a big promotion at work, but quickly realizes she may never escape the high demand for serial killer reports.

The team investigates the murder of an architect who was tasked with renovating a supposedly haunted hotel.