The official story is that Garrett Wheeler, the Sentinels' chief, is dead - killed in a covert op gone horribly wrong. But Alexa Marlowe - his ex-lover and most trusted agent - isn't buying it. Overnight, a new leader has mysteriously assumed control of the elite vigilante organization, a man Alexa Marlowe can't afford to trust. In search of Garrett and the truth, she goes rogue and off the grid, following a deadly trail that leads into Mexico, behind the fortress walls of a murderous drug cartel boss. Alone, Alexa has no one to watch her back, not even her new partner, Jessie. Ex-bounty hunter, Jessie Beckett, has troubles of her own. Her world is turned upside down when her DNA turns up as evidence in a gruesome murder committed when Jessie was only a child, before her life was shattered by an infamous killer. Solving a very cold case may hold the key to who she really is or kill the only memory she has of a woman she believes is her mother. For Alexa and Jessie, the dead must have a reckoning.