In 1899, Dr. Alexander Hartdegen is an inventor teaching at Columbia University in New York City. Unlike his friend David Philby, Alexander would rather do pure research than work in the world of business. After a mugger kills his fiancée, Emma, he devotes himself to building a time machine that will allow him to time travel to save her. When he completes the machine four years later in 1903, he travels back to 1899 and prevents her murder, only to see her killed again when a horseless carriage frightens the horses of a horse-drawn vehicle.