When a beautiful woman staggers into the street and collapses from an apparent overdose, Andy and Marlo chase down her dealer, tackling him in a cloud of powdered heroin. The arrest sends 15 Division into emergency response mode when the drugs prove to be laced with deadly bacteria. Led by Swarek, the troops scramble to get the contaminated heroin off the streets before a deadly outbreak sweeps through the city. Andy and Marlo are plunged into an awkwardly intimate decontamination process, forcing Marlo to expose a shocking secret. Meanwhile, Dov and Chloe comfort a man whose wife has fallen victim to the dirty drugs, and their budding romance is threatened when Dov suspects Chloe of harboring a dark secret.
A fun, fresh, high-stakes drama with a twist of danger follows the lives of five young, ambitious cops right out of the Academy. From their very first day on the job, these rookies are plunged into the world of big city policing, a world where even the smallest mistake can have life-or-death consequences and serious emotional fall-out.
The soul of this close-knit group is 26-year-old perfectionist Andy McNally. Honest to a fault, all Andy has ever wanted to be is "good police". Her father was a cop, and while he wasn't the best cop - or the best father - Andy knows she'll never find this sense of family, loyalty and excitement in any other job.
The series explores the trials, triumphs, competition and camaraderie of Andy and her rookie family - boyfriends, best friends, mentors and competitors - who are about to learn that no amount of training can prepare them for life.