While Castle is filming for a multimedia campaign to launch his latest thriller, a serial killer remains ahead of the NYPD, murdering people and leaving plenty of provocative clues. While media pressure rises, the team painstakingly find out the victims all link to the Wilder brothers' anonymous social media website. Finally, they must race against the ticking clock as two last murders are set to happen live on the Internet while the suspect is in police custody.
—KGF Vissers