New Mexico Territory, 1861: A secret document disappears during the infamous Butterfield Station Massacre - and with it any hope of quickly ending the west's bloody Indian Wars. Arizona-Mexico Border, 2016: During a deadly firefight against white supremacists, US Immigration Agent Jason Holt uncovers evidence of a 150-year-old treaty that traces back to Abraham Lincoln's White House. Jason's discovery triggers the implementation of a long-forgotten Presidential Directive - protect the treaty's secret at all costs. The FBI orders outcast Agent Sara Navaro to eliminate the threat. But killing...