Jeff and Bogg arrive in the Cuban revolution, to find history changed because Teddy Roosevelt never led the charge up San Juan history. He was killed by Billy the Kid in 1889. The Voyagers head back to that time, stopping briefly to help Ben Franklin get his kite in the air. Once back in the Old West, the two infiltrate Billy's gang and then save Roosevelt's life. Billy turns out to be a coward without his gun, much to Jeff's dismay. Travelling back to Cuba to make sure history is on track, they meet up with Roosevelt and help the Cuban rebels, setting history right.

In order for the future American Space Program to succeed, the Voyagers must go back to Austria just after the end of World War II and prevent rocket scientist Werner Von Braun from being captured by the Soviets.