The director of the US National Undersea Research Administration, Dirk Pitt Sr., received an urgent task of the highest degree from the government. He and his team need to find a missing submarine designer who recently introduced a fundamentally new type of engine into production. With such new weapons, the United States will be several decades ahead of the rest of the world. The new submarine of the Poseidon Arrow type is already ready for launch - and its creator has disappeared along with a prototype engine and design documentation... Pitt understands that there are many who want to acquire technology of this level. But who exactly? To find out, the director of NUPI will have to cross half the world, constantly risking not only his life, but also the lives of his colleagues, and even his children...