Castle (2009): Season 6, Episode 6

6 - 6: Get a Clue

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.