Castle has some very special themed episodes coming up in season 4, including the possibility of Ryan and Jenny tying the knot. Seamus Dever spoils that the upcoming nuptials won't be all sunshine and rainbows. In fact, it will leave Ryan and Jenny both stressed to the hilt. EP Laurie Zaks revealed that on Halloween night a Ghostbuster themed episode will air. is hoping that the ghostbuster that made Stay-Puff famous, Dan Aykroyd, will guest star. Last, but certainly not least, the hit series is planning it's first Christmas show. There are rumors flying all around that this episode may be when Richard gets to meet his long lost dad. Below is the official Season 4 promo for Castle.
Source: TV Guide