Hood and Rachel head to a college campus in Oklahoma where two students have died of "the bends" but neither one was even in the water, much less diving. As a third victim falls just after their arrival, they're able to stabilize him temporarily in a pressure chamber, but it increases the pressure on Hood to figure out what is causing this reaction. Hood determines physical exertion triggers the reaction that causes the bends, and that all the victims had mysterious flu shots before this event. Hood works to solve what is causing this mysterious reaction which turns out to be a sophisticated form of gene doping which is a virtually undetectable way of enhancing athletic performance. As Hood races to find a cure, Rachel partners with the school's head of security officer, a former FBI agent who assists her in tracking down the perpetrators and their other victims.