Once inseparable, old-school cops Michael "Mike" Lowrey and Marcus Burnett are coming apart. Burnett has now become a police inspector while Lowrey, who is suffering from a midlife crisis, is assigned to lead the newly created elite team AMMO even though he has nothing in common with the millennial cops that make up the team. When a ruthless mob boss from a Miami drug cartel, whose brother Lowrey and Burnett took down years earlier, makes a retaliation effort on Lowrey just when he and Burnett are about to retire, the duo must reunite to take him down.