Brianna Haynes impresses in a tiny role -dead before the opening (but acting real dead plus in flashback music video footage) as a murdered rock star named Hayley Blue. Her surviving sister Sky Blue played by Erin Foster is the real star of the episode who gets to sing at the end, and I was immediately sucked into the story, as that is the stage name of two famous porn stars from two different eras, but this segment of "Castle" is not about just sex per se, but the loose living of the rock celebrity milieu.
The hunt for the killer is rather mundane until he ineresting incest-tinged final revelaton -I'm sure this episode would have been much better had there been more music integrated into the story and, better yet, if real-life rock talent had been hired to portray fictional musicians in the narrative. That idea would likely have been blue-penciled as too expensive.