When a crew of violent eco-terrorists abducts the teenage son of an energy company executive, SWAT must untangle the kidnappers' twisted motives before carrying out a high-stakes rescue mission. Meanwhile, Hondo's involvement in a shooting draws outrage from the very community he's dedicated his career to protecting. And, as Deacon is called on to help with the escalating crisis, he's forced to confront nagging doubts about his retirement.

SWAT faces their deadliest adversary yet when a violent cell of extremists looks to extract vengeance by blowing up half of Los Angeles, potentially killing thousands.