Castle and Beckett look into the murder of a young mathematician gunned down with a 200-year-old bullet, sparking some wild theories by Castle about a time-travelling killer. When their investigation uncovers a tricked-out DeLorean and a suspect in Victorian clothing, is it possible Castle's crazy idea has some validity? This winding tale twists through the towers of Wall Street and into the world of a secret steampunk society that embraces the romance and simplicity of the past, while coupling it with the hope and promise of the future.
When a coded document hidden by a murdered bail bondsman gets Castle's imagination running wild, Beckett must steer the case back to the violent felons who populated their victim's world - only to discover that maybe Castle's crazy theories aren't so crazy after all. Complicating matters is the surprise arrival of Beckett's ex-partner (now a bounty hunter). As the two reunite over a history that Castle has no part of, Castle is forced to watch the relationship take a turn towards the romantic.
When a famous psychic is murdered, Beckett and Castle search for her killer while also carrying on a spirited debate on the existence of extrasensory abilities. Evidence mounts on both sides, especially when a letter arrives from the victim, penned the day she was killed and predicting her own death -- or was it written by a clever killer, hoping to throw off the investigation?
Beckett hasn't heard from Castle since he left for the Hamptons months ago to finish writing his second Nikki Heat novel, "Naked Heat" (on sale September 28). The most Beckett, Ryan and Esposito have seen of Castle is a bookstore standee of him advertising an upcoming book signing. So when Beckett and her team burst into a shadowy apartment on the trail of a murderer, the last thing they expect to see is the real-life Castle standing over a dead woman's body holding a gun! As Castle protests his innocence, Beckett has no choice but to arrest him on suspicion of murder.