While investigating a shocking ritualistic murder, Beckett and her team uncover surprising evidence linking Castle to the killing. As the evidence against him mounts, loyalties are tested, and when surprising revelations come to light, Beckett begins to wonder how well she really knows her new lover and partner of four years.

When the lead guitarist of a rock band is murdered, the documentary crew that were following the band turn their cameras on Castle, Beckett and the team as they try to solve the case. The result is a documentary style episode of "Castle," which offers us a unique glimpse at our characters as they navigate a world that goes far beyond the rock & roll stage.