The secret on set
(Book)

"Working on a Hollywood set, Hayley's seen all kinds of creepy special effects. When she comes across what appears to be a dead body under a sheet at Silver Screen Studios, though, she's sure she's found evidence of a real crime! But when she brings the security guard back to the scene, the body has vanished, and it seems someone in the cast or crew is playing a mysterious prank. Could the culprit be the show's latest guest star, who's famous for his vampire films? It's up to Hayley and her two best friends to find out!" --publisher's website.