It will be from Kate's POV. It starts in ep 09 in s 04 (Kill shot). Kate is still with Josh but they have lots of fights. And he maltreats her. He rapes her but she doesn't tell anyone. She loves Castle but Rick doesn't know it.

Castle and Beckett had been married for three years. They had been trying to have a baby for two and a half of those years. They finally decided to go to the doctor to see what was wrong. Will what they find out tear them apart, or give them blessings they never expected? (Rated mature for safety because of occasional cussing.)

Kate Beckett has been a fan of criminovelist Richard Castle ever since the first book, but when she starts researching about becoming a foster mother she gets shocked to see his daughter, Alexis Harper Castle, is one of the kids who needs a foster home, fast. Kate immediately jumps in and goes through all the tests needed to be accepted as a foster mother for the girl. As time goes Kate can't help but fall in love with the girl and wants to treat her like her own. One night she gets in contact with the man she shouldn't have contact with, and before she knows it she's agreed to meet him. She doesn't tell anyone because if the word would get out someone might take the girl away from her. Her detective instincts kicks in and she can't help but question why Alexis was taken from her dad. That's when she can't shake the feeling that mr Castle is falsely accused for whatever it might be and decides to try and find out more. Not knowing it would lead back to her own past. And there was nothing she wanted to get away from more than the hell she had gone through. I DO NOT OWN THESE CHARACTERS, ALL RIGHTS TO ABC'S CASTLE!

Kate Beckett or, as you might know her, Nikki Heat has been in the business since she was sixteen years old. And everything was fine, or at least so she thought it was, until she met him. He wasn't like the others, he didn't understand it was a job. Because it WAS. A. JOB. It was HER job. Her job to satisfy his, and others', needs. But what does one do when the job turns into more?