金·惠勒是一名律师，她被任命为内华达州法院第五地区的法官。随着对前任法官死亡案件的调查升级。她的妹妹，一个经营当地妓院的人，成为了主要嫌疑人。

San Antonio, Texas. The bodies of various drug cartel members are turning up mangled and drained of blood. Tough DEA agent Carlos Seguin discovers that the grisly murders are being committed by a pack of chupacabras, which are lethal predatory creatures of local legend. Carlos, his feisty new partner Tracy Taylor, wayward estranged son Tommy, and several others make a desperate last stand against the bloodthirsty beasts at the famous fort The Alamo.