During the Boxer Rebellion in China during the early 20th century, in which a Chinese secret society attacked all westerners and anyone who associated with them, Dr. Fu Manchu's wife and child are killed by foreigners. Enraged, he vows to take his revenge on the British army officers he holds responsible for the killings.
Harold "Speedy" Swift, a fan of Babe Ruth and the New York Yankees, saves from extinction the city's last horse-drawn trolley, operated by his girlfriend's grandfather.