Wyoming Territory, 1873. Tim Colter and his trusted guide, mountain man Jed Reno, are on the trail of a vicious gang of train robbers when they happen upon a bloody and shocking scene. Lying on the ground, barely breathing, a Secret Service agent has been left for dead in the wake of a brutal ambush. His final words: 'President Grant ... assassination ... Dugan ... trust nobody.' It's a message that chills Colter and Reno to the bone. President Ulysses S. Grant is scheduled to arrive soon in Cheyenne. Dugan is a former Confederate guerrilla who leads a notorious gang of cutthroats. And the agent's last words - 'trust nobody' - suggest this conspiracy could reach to the highest levels of American power. Colter and Reno are determined to stop the assassins by any means possible - even if they have to enter hell itself, better known as Dugan's Den. But to get there, they'll have to bust a lady outlaw out of prison then convince her to take them to Dugan's hideout - with a lunatic killer on their tail and the president on a collision course with death ...