A young Fae woman discovers the dark market value of her own blood after a knight's warning and her best friend's investigation into a dangerous new drug. Ruby Morgan's Christmas vacation is shattered by the arrival of an Avalonian knight who warns of a fugitive targeting her mother due to her pure bloodline. Simultaneously, her best friend, Charlie, uncovers an underground market dealing in PureX, a drug derived from pure-blooded Magicals. Ruby is drawn into investigating this illicit trade, realizing her own blood might be the key commodity, and the knowledge of its worth could come at a devastating price.

The premise of Virtues of Purity sets up a high-stakes urban fantasy narrative centered on a young protagonist caught between magical heritage and dangerous criminal elements. The inclusion of a drug trade involving magical blood suggests a focus on themes of exploitation and the commodification of identity. The series context implies a continuation of established world-building and character arcs, likely appealing to readers invested in the ongoing saga of Ruby Morgan and her world. The narrative structure, as indicated by the description, appears to be driven by immediate threats and investigative action.