The dramatic impacts of global warming have led sea levels to increase in 2039, resulting in significant land loss. A fleet of formidable warships equipped with modern weapons emerges to ensure mankind learns its lesson, bringing devastating loss for naval forces throughout the planet. The Fleet of Fog has a "Mental Model," a humanoid avatar that symbolizes the ship's heart, its "Union Core." Each model has a different personality, but they all follow an unknown authority known as the Admiralty Code, who have imposed a blockade to prevent humanity from crossing the sea.