The bodies of high school and middle school kids are found dead from an overdose of heroin and fentanyl. The drug trade along the I-94 and I-43 corridors and the Milwaukee Metro area are controlled by MS-13, a violent gang originating from El Salvador. Ricardo Fuentes is sent from Chicago to Waukesha to find out who is cutting in on their business, shut it down and teach them a lesson. But he has an ulterior motive: find and kill a fifteen-year-old boy, George Tokay, who had killed his cousin the previous summer.
Detectives Jamie Graff, Pat O?Connor and Paul Eisenmann race to find the source of the drugs, shut down the ring, and find Fuentes before he kills anyone else, especially George or members of his family. The three detectives discover the ring has its roots in a high school among the students and staff.