Andrew Tan's story happened more than 100 years ago, and the Spanish-American War was about to break out. In order to gain the initiative on the battlefield, President McGinley of the United States urgently needs a suitable messenger to deliver this letter to General Garcia of Cuba. The military intelligence agency recommended Andrew Tam to the President. After receiving the task of "delivering letters" given to him by the President, Tan immediately carried it out unconditionally, overcoming all kinds of difficulties that ordinary people could not overcome, regardless of personal life and death, overcoming difficulties and obstacles, and finally delivering the letter within the scheduled time.