It was Bracken who told Rick when the latter visited him in jail that Kate will never be happy just being Mrs. Castle. He said that even though Kate seems as if she’s got it all together, it would be impossible to simply push away her 16-year-old obsession with putting Bracken away for his crime.
It has been reported before the Season 8 premiere of “Castle” that Kate’s promotion as Captain of the 12th Precinct will drive a wedge between her and the two detectives who have been her and Castle’s rivals in solving crime cases in the force – Kevin Ryan, played by Seamus Dever, and Javier Esposito, played by Jon Huertas.
The envy and pressure for Ryan on Beckett would further be heightened with the birth of another baby with wife Jenny Ryan, played by Juliana Dever.
Co-showrunner Terence Paul Winter confirmed the new member coming to the Ryan family and also teased that the new baby will shake things up in the precinct.
According to Winter, Ryan’s new baby will make the detective even more paranoid and excited about trying to make more money. And when he sees that Beckett is already up in the ranks, he will realize that it is time for him to start looking into the future of his family, which will create some tension and conflict between them.
But such subplot has not been highlighted yet during the Season 8 premiere of “Castle” and it will most likely take shape in the subsequent episodes.