While Kit Carson defends a small ranch from an attack by a gang of hitmen, without being able to save the owner, Tex and Kit, in Phoenix, witness a mysterious and spectacular crime, in which their friend Sheriff Patterson is seriously injured. The two bloody events seem to have nothing in common, except a city in the past of the two victims: Deadwood. On the trail of the assassins, the three pards are about to encounter a dark intrigue whose stages are marked by five playing cards: two aces, two eights and a jack of diamonds... In pursuit of the accomplice in the murder of Deadwood Dick, a certain Luke Harrigan, Tex and Carson arrive in Albuquerque, where the trail is lost. Tex has only one faint hope left: that of finding Harrigan on the midday train headed to Colorado. If successful, he and Carson will be able to learn who instigated the murder and begin to solve the complex puzzle linked to the death of Wild Bill Hickok. Meanwhile, on the trail of the faceless avenger who killed Mr. Black leaving an eight of spades next to the corpse, Kit Willer finds another dead man, another playing card and a mysterious Dakota Indian who keeps his mouth tightly shut In search of the mysterious avenger who leaves a card from the "dead man's hand" next to each of his victims, Kit Willer reveals the enigma of the mysterious "Lonesome Prairie". While, in the turbulent city of Deadwood, Tex, Carson and Luke, between about-faces, ambushes and shootouts, meet the last instigators of Wild Bill's assassination. At their side, for the final showdown, they will have an unexpected ally
