On the eve of World War III, the best scientists on the planet founded Underwater Colonies in the depths of the World Ocean. The nuclear nightmare of the global apocalypse threw the inhabitants of Sushi to the level of primitive savages, who had to restore their civilization for an excruciatingly long time. Two hundred years have passed. Underwater Colonies have made unprecedented progress and are ready to harshly defend their interests. They provoke the beginning of the war with Susha, moving from the tactics of force deterrence to an open armed offensive. Employees of the Main Directorate of Underwater Colonies Mark Agee and Artemy Valevsky are drawn into the whirlpool of military events.