Returning from a year-long psychological leave of absence after surviving an almost-fatal gunshot wound to the head, Detective David Creegan is assigned to the FBI's Organized and Serial Crime Unit – a rapid-response, elite crime investigation squad – where he and his new partner, Detective Susan Branca, find themselves committed to saving lives and solving cases. In spite of his inability to abide by common sense and the laws he's sworn to uphold, Creegan, with the help of Branca, works on hunting down the most vicious criminals on the streets.