It's a steamy, restless end of the school year in New Orleans. Sister Holiday is busy teaching music classes and preparing for her permanent vow ceremony, a pivotal moment in her journey of faith. But when one of her favourite students is found dead of a fentanyl overdose, Sister Holiday and her partner-in-PI, Magnolia Riveaux, are launched on a mission to track down the drug dealers.

As students continue to fall prey to this sinister drug under her watch, Sister Holiday becomes more and more desperate to stop the epidemic. All the while, she must contend with her own past with addiction, a demon that is never too far.

As she goes deep undercover with a local gang, Sister Holiday's darkest and most shocking case yet will test the limits of her faith-and her sanity.