When Robin and Loretta’s conflict escalates, Barney is caught in the middle. Meanwhile, Marshall and Daphne deal with a stowaway on their road trip, and Ted and Cassie try to enjoy a trip to a lighthouse.

Alicia and Cary represent a client who changed firms and Will and Diane delay turning over the case files. Marilyn tries to give advice to Alicia.

Carrie turns the tables on the mastermind of the Langley bombing, but recruiting one of Iran’s most powerful operatives has dangerous consequences. Meanwhile, Saul struggles to keep an intrusive Senator Lockhart at bay, and Dana makes a radical decision that will change the Brody family forever.

When Captain Gregson’s home is invaded, Holmes and Watson work to find the masked gunman before he strikes again. Meanwhile, Gregson gives his team some insight into his private life.

The team investigates Democratic Congresswoman Josie Marcus, while Olivia and Mellie have a surprising run-in during the White House Correspondents’ Dinner. Meanwhile, Jake and Huck get closer to the truth about Operation Remington, which could lead to devastating results.

As Peter settles into a promoted position at the FBI, Neal has to pull off a brazen museum heist right underneath the FBI’s nose.

Sue holds a seance with her friends; the football team stops Axl from attending the Halloween party in his room; the family tries to give Brick advice about girls.

Oliver discovers a man who goes by the name “The Mayor” is bringing illegal guns in to The Glades, so Oliver sponsors a “Cash for Guns” event to help clean up the city. Unfortunately, The Mayor crashes the event with his gang and seriously injures Sin. The Canary is furious when she learns her friend is in the hospital and sets out for revenge. Meanwhile, Felicity stuns Oliver with a bit of information about the Canary, Donner asks Laurel to dinner, and Diggle reconnects with an old friend.

As Charlie, Rachel and Gene question Monroe’s true allegiance, Miles himself is weary of his former friend’s intentions. Meanwhile, Aaron continues to have visions that lead to endless questions.

Castle and Beckett investigate the bizarre murder of a young woman who was found ritually posed. When the team finds a collection of strange symbols in her apartment and the prime suspect turns out to be a mysterious monk, Castle becomes convinced they’ve stumbled onto a “Da Vinci Code” style conspiracy. Meanwhile, Castle tries to come to grips with the fact that Alexis and Pi have moved in together.