With Beckett still in D.C., Castle and the boys investigate the murder of former child star Charlie Reynolds, who rose to fame playing the lovable nerd on an early 90s High School sitcom.
A bleeding man stumbles into a church, but just before dying, he hands a mysterious bundle to the priest. When the bundle turns out to be a smiling baby boy, Castle and Beckett find themselves accidental nannies to the newborn.
Castle and Beckett discover that the victim of a building fire was actually shot to death, they get on the trail of a serial arsonist turned murderer. Meanwhile, Ryan’s wife, Jenny, goes into labor, but disaster threatens to ruin the joyous moment.
Castle and Beckett investigate the death of a young girl who appears to have been killed with telekinesis.
A desperate young murder suspect, Emma Briggs, takes hostages at gunpoint then mysteriously insists that she will only negotiate with one person: Richard Castle
Alexis enlists Castle's help on an Innocence Review case to prove that a death row inmate, Frank Henson (guest star James Carpinello, "The Good Wife"), was wrongly convicted.
The murder of a young video store clerk takes a strange turn when the team discovers his past history as a high-level hacker. But it’s nothing compared to the shock Castle receives when their investigation leads them straight to his father, Jackson Hunt.
A guilt-ridden woman confesses to a murder, but contradictory evidence and a second confession complicate the case.
The team must pretend they're in the 1970s when talking to an old-time mobster.
Castle and Beckett's long-awaited wedding is almost here, but when a shocking surprise threatens to ruin the big day, they are sent on a wild mission filled with masked men, angry bikers and a charming ne'er-do-well from Beckett's past.