When Owen Galloway, the track star son of a prominent US senator, is found dead of an overdose in his bedroom, LAPD Detective Cari Garcia suspects that he's just another teenager who hid a drug addiction. In Vancouver, Dr. Julie Rees, an experienced toxicologist, notices a growing number of overdoses among the eating disordered and body builders, and mentions it to her boyfriend, Detective Anson Chen. Then Rain Flynn, a famous pop star and social media influencer, dies in her Vancouver hotel room showing the same symptoms of a fatally high fever and uncontrollable seizures as Julie's other ER patients, including the coowner of a wildly popular wellness center with locations in both Vancouver and LA. After an autopsy confirms that Rain overdosed on illicit diet pills containing a deadly toxin known as DNP--an explosive agent originally used in the trenches of World War I--the media gets hold of the story and runs wild with it. But who's behind the online marketing and distribution of DNP? And how is the wellness center connected? The daunting challenge of putting the pieces together falls to Detectives Garcia in LA and Chen in Vancouver. Can they solve these crimes before DNP becomes the next viral TikTok challenge?