In 1880, during the War of the Pacific between Peru, Bolivia, and Chile, the dictator of Peru hires Paul Boyton and George Kiefer to help break the Chilean blockade of the harbor at Callao, outside of Lima. Boyton plans to navigate out in a rubber life-saving suit and attach torpedoes to vessels in the blockading squadron. Boyton and Kiefer will attempt their task under the advance of the Chilean army, as it soundly and mercilessly destroys the remnants of the Peruvian defense and marches towards Lima. The United States tries to mediate the conflict, sends naval observers, and monitors Peru's leadership struggles, while the citizens of Lima fear for their families and possessions.