时长:00:41:53 / 首播:2016-02-08
A body is found during Martha's singing rehearsal, of an ex-con turned a-capella singer. Castle, Beckett, and the team enter the world of competitive a-capella. At the same time, to keep up the act that Castle and Beckett are still separated, they act infuriated towards each other in front of Ryan and Esposito, but their acting works too well. They now think that Castle and Beckett are having an affair with a sexy Russian model named Svetlana, and a Dr. Livingstone, respectively.