Teenage rebellion at last The case was interesting, however this episode was really more about the relationship between father and daughter.
Alexis had a point. She has put up with a lot from her father over the years. She has always gone along with his craziness, even when she didn't understand or agree with the things that he did. It's his turn to accept the changes in her life. Kate also had a point. The more Castle objects to Pi, the longer he will be around.
Anyone who has ever been a teenager in love knows that first relationships are not about winning parental favor. In fact, just the opposite. It is about breaking away from your parents and trying to find your own path. In fact, often the closer the bonds are between parent and child, the more extreme lengths they may go to in order to declare their freedom and independence. It's all part of growing up and discovering who you are. And who you want to be.
Castle needs to take a step back and allow Alexis to figure out where she is going. She has always been an extremely intelligent overachiever. Right now she is exploring the dreamer side of her personality that she has kept suppressed. She will probably grow tired of Pi in a short time. They really don't have a lot in common. Unless her dad keeps pushing that is. Then she will be forced to continue defending him as a way of standing up for herself and her right to make her own choices.