Ep 11. Under The Influence

In season 5 episode 11 of Castle entitled Under The Influence, Castle and Beckett are called to the scene of a construction site where a body was found locked in a wall. The investigation leads them to a group of college students who have been partying hard and whose behavior has been influenced by a designer drug called "Triple X". The detectives must navigate through the world of drug dealers and partiers to uncover the truth about the victim's death and the source of the drug.

As they investigate, Castle and Beckett also navigate their own relationship struggles. Castle is conflicted about his role in Beckett's life and his own feelings towards her. Meanwhile, Beckett grapples with the emotional fallout from her previous case where her partner was killed, while also questioning her career choice.

With the help of a streetwise informant and some creative investigative techniques, Castle and Beckett slowly uncover the truth about the drug trade on campus and the victim's connection to one of the group's party promoters. However, just as they get close to solving the case, a shocking twist reveals a new suspect and throws their investigation into disarray.

As the team races against the clock to bring the culprit to justice, Castle and Beckett come to a new understanding about their relationship and what the future holds for them. With plenty of thrilling action, mind-bending plot twists, and emotional drama, Under The Influence is an exceptional episode of Castle that will keep you on the edge of your seat from start to finish.