When an Arctic explorer is killed during a polar expedition, the mysterious circumstances of his death take Castle and Beckett from the penthouses of Park Avenue to the halls of the CIA. But Castle's delight at the case's many twists and turns soon turns to frustration as he realizes that their elusive killer might just be fooling them all.
Illegal Czech immigrant Eliska Sokel's corpse is found hidden in a sewer, two days after her death. Her also-illegal ex, Teodor Hajek, explains she left him after their son died from a congenital disease. She had worked on the concierge staff of a luxury residence but was fired after Dr. Cameron Talbot's wife questioned the appropriateness of her treating their son Zane to a lollipop. Castle wonders how Beckett will take his dedication of a book starring her alter-ego, and his agent Haas's offer of a contract to write 3 British spy novels. They still solve the case ...
Highly respected A.D.A. Jack Buckley, a tough crime-fighter, was murdered. His brother in law, businessman Paul Cho, was blackmailed mysteriously with his use of call girls from 'Danton.' Team Castle discovers it's all about the discreet cyber-pimp business, which also employs Buckley's legal protégée Scarlett Price. While working out who succeeded jailed founder Dan Tonelli, 'cool dad' Castle worries which secret Alexis shares only with Becket.
When an art dealer is gunned down in his gallery, Castle & Beckett discover that a bullet is inexplicably missing from the crime scene. The mystery is deepened by an amnesiac who witnessed the crime but can't remember what he saw or even who he is.
While investigating the death of an Irish mobster, Beckett and Castle uncover a local turf war that may be connected to both a late-night infomercial guru and an international drug smuggling operation. But the case turns agonizingly personal when evidence emerges that the killer they're chasing may have had a hand in Beckett's mother's murder.
Mysteries abound when a family returns from vacation to discover a dead man in their daughter's bed. Thinking they're investigating the murder of a squatter, Castle and Beckett soon find themselves unraveling a multi-million dollar heist. Meanwhile, Castle tries to keep Beckett from finding out that they've been romantically linked when he's featured as one of New York's 10 most eligible bachelors.
The investigation into the shocking death of a museum curator, crushed by a falling gargoyle, takes a bizarre turn when Castle and Beckett learn that he isn't the first member of a recent archeological expedition to die. It turns out there was a legend inscribed over the burial chamber the team unearthed warning that "all who gaze upon the face of the mummy are doomed." Was the curator just the latest victim of "The Mummy's Curse"? And if so, what does that mean for Castle, who snuck a peek at the mummy when no one was looking?
Nothing is as it seems when Castle and Beckett investigate what appears to be the assassination of an intelligence operative. Meanwhile, Beckett's romance with Demming threatens her relationship with Castle, forcing them to confront their feelings for each other.