In this third installment of the critically acclaimed New York City firefighting suspense series, Fire Marshal and single mom Georgia Skeehan investigates a ferocious, deliberately set blaze that kills two firefighters and traumatizes a young rookie. She and her partner quickly find the suspect, a vicious arsonist known as the "Freezer" who has evaded prosecution for decades. There's just one catch: he's an FBI informant. The Bureau is using him to bring down a shadowy group plotting a crime of unprecedented proportions. Georgia's only hope of brokering a future prosecution is to accept the FBI's offer to go undercover with this slick arsonist. But once inside, she comes face-to-face with the last person she expected to see: the long-estranged father of her young son. Is he behind the plot? As Georgia races for answers, she uncovers a chilling connection between her current investigation and a long-ago blaze that changed her life forever. The hunt for vengeance could cost Georgia everything: her job, her relationships—even her life.