It looks like the writers tried to capitalize on the Leno/Conan debacle a while back, so this episode featured Tom Bergeron as Bobby Mann, a talk show host past his prime. He tells Castle he's in danger, and when he's is found dead, Castle knows something is up despite no distinct evidence. The case is rather standard and after interrogating multiple people, it turns out that Mann's partner played by Fred Willard was the murderer.
The subplot was funny stuff as usual. Castle hooks up with an actress who just happens to be recommended as Nikki Heat for the movie. Beckett, tipping her hand, worries that the actress is sleeping with Castle to get the part. It's a fair point, but Beckett, who says she doesn't care about Castle's personal life, is really involved. Castle has another date at the end of the episode--with Alexis--but doesn't tell Beckett upfront. She nearly freaks out before Castle tells her to truth.
Score: 8.7/10