The Voyagers inadvertently bring Cleopatra forward in time to prohibition-era New York City, where she encounters gangster Lucky Luciano. In the main plot, Phineas has to convince young baseball player Babe Ruth to abandon his pitching career so that he will eventually become the home run hitter idolized by Jeffrey.

On their way to rescue President Lincoln, who has been kidnapped by Confederate soldiers, the Voyagers are briefly diverted to 1832 London where they encounter young author Charles Dickens.

Jeff and Bogg arrive in 1930's New York and meet a retired adventurer/voyager, Isaac Wolfstein. They drop him off on an island to live out the rest of his life, save Albert Einstein, then pop back to Marco Polo's time...but Polo isn't where he's supposed to be. The two try to restore histroy but Jeffrey is caught by soldiers who plan to sell him as a slave. Bogg goes to Wolfstein to get advice, and just manages to save him from a nuclear test on the island. The two men return to save Jeffrey, then head off to lunch with Einstein.

The Voyagers appear in 1890 in Texas, and find that Dwight Eisenhower's mother is unable to give birth to him because of the absence of a doctor. They are unable to call for help because the telephone doesn't exist! Travelling to 1875 Boston, they try to find what happened to Alexander Graham Bell. Bogg rescues a young deaf girl, and then they find out that Bell discontinued his experiments due to a lack of funds. Jeff remembers that Bell got his money from his fiancee, who turns out to be the deaf girl Bogg rescued. They must unite the couple, but Bogg falls in love with the girl in the process. Eventually he leaves her so that history can stay on track. After checking a few months down the road to make sure Bell does indeed invent the telephone, they return to 1890, where things work out and Dwight Eisenhower is born, setting history back on track.