In 1870, the soldiers of an Army outpost in Utah are supposedly suffering from a diptheria epidemic. Fortunately, a train, filled with additional soldiers, medical supplies and a motley crew of passengers, is on its way. One traveler is John Deakin, an undercover agent posing as an arrested criminal. When Deakin begins snooping around, he makes a stunning discovery: that there is no epidemic at the fort. The lie is actually part of a conspiracy between a group of killers and a tribe of Indians, who plan to take over the outpost and steal its gold and silver. Can Deakin foil the plan before it's too late?