Complete story — includes the ending
Castle and Beckett investigate the murder of a ghost hunter named Jack Sinclair who was looking into a haunting at a New York mansion. As they delve deeper into the case, Castle supports the idea that supernatural powers could be at work, while Beckett looks for a non-supernatural reason for the murder. While looking at the haunted mansion, Castle and Beckett discover a secret alcove where the killer killed Jack Sinclair, putting Castle's "demon" theory to rest.
Sources and content license
Source and revision history · Adapted from Wikipedia contributors, Castle season 4. HTML formatting and reference markers removed. · Content license