Death of a Prom Queen is one of Castle's bestselling novels written in the years before he met Beckett at the start of the series. It is one of his 'standalone' books, not part of the Derrick Storm series. Although referenced in the show, it has never been made available in the real world.
(From richardcastle.net) Just a week away from her high school graduation, valedictorian Cassie Evans can’t wait to get out of her boring small town of Saltee, North Carolina. But after the prom queen turns up dead in the school swimming pool, a knife sticking out of her back, Saltee quickly becomes far from boring. When two more seniors are murdered the next day, it’s clear that someone is taking out Cassie’s graduating class. The entire town is swiftly torn apart, as fear and suspicion erupts into violence. As Cassie tries to discover the killer by digging into the lives of her neighbors, she soon finds that everyone has something to hide. But can Cassie uncover the killer’s secret before she becomes the last living senior in Saltee?
References in Episodes
Flowers For Your Grave (episode 1.1) – 3rd murder victim from book, Kyle's apartment