Castle and Beckett investigate when a beloved former major league baseball player is found dead after a goodwill trip to Cuba.
A night of partying ends badly for an American in Tijuana; Jack comes across his son working undercover with the Mexican cartels.
Calvin decides to splurge on an expensive jacket, then worries it's too special to risk wearing outside the house; Dave and Gemma worry their new friends' daughter is a bad influence on Grover.
In order to protect his best friend and main informant, Deeks resumes a former alias that he dislikes.
Eight months later, Savi makes the most of her second chance. Meanwhile, Karen struggles to rebound from loss.