CASTLE – “Probable Cause” – 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, on “Castle,” MONDAY, OCTOBER 29 (10:01-11:00 p.m., ET) on ABC. (ABC/RICHARD CARTWRIGHT)