When Detectives Quinn and Vince investigate the shooting of Antwan Curry, they find a trail of blood leading away from the murder scene; they set out to find the injured person, not knowing if they're looking for another victim or the killer.

After immigrant Mamadou Berry is murdered, Quinn and Velazquez seek to find his killer; the yearlong investigation pits the detectives against the International Robbin Crew, a ruthless and deadly Atlanta gang.