Second Great War at Sea: Tropic of Capricorn told the story of a war that never happened: a naval conflict between Argentina, Chile and Brazil breaking out in 1940 as part of the world-wide Second Great War. Tropical Storm picks up the story, as a German squadron arrives to aid the Brazilians and the naval war continues. Like all the other Second Great War at Sea games and books, Tropical Storm uses the rules from Second World War at Sea and is fully compatible with that series historical games.