The end of October in 2004 heralds the start of a cold winter for Alex Boswell, a veteran NYPD homicide detective, world weary and cynical, but dedicated to the job. He is investigating an armed robbery in Harlem and the death of an assistant district attorney on the Upper West Side when he starts experiencing mystifying flashbacks and panic attacks. He’s baffled but doesn’t want to think about it too much; not in the NYPD where toughness is prized and admitting to mental health problems could ruin his career. While his cases end up in legal quagmires, he tries to cover up his illness, but his condition deteriorates, and he can't hide it anymore, not when he's having attacks in court or while searching apartments. Finally, his lieutenant orders him to see a psychiatrist. The doctor diagnoses him with post-traumatic stress disorder and unravels the trauma behind the flashbacks – a cop-shooting in 1987 and a car accident in 2002. As Alex takes medical leave, he wonders if he will ever get well enough to return to the homicide squad.