Adam Baldwin guest stars as Ethan Slaughter, a detective Castle shadows while he deals with his situation with Beckett.
- Slaughter is a tough cop chasing down a murder between gangs.
- Beckett, Ryan, and Espo are annoyed at Castle spending time with another detective.
- Slaughter takes Caste through some rough situations while they track down the murder of a kid.
- The kid was trying to prove himself to his gang and got caught up. He called his father who then killed him.
- Beckett talks to her therapist about Castle. She thinks she may have waited too long to acknowledge Castle’s “I Love You.”
- Alexis gets her college acceptance letters and is accepted to Stanford.