The film opens on the fictional island of Svardlov in the far North Sea above the Soviet Union where an American spy breaks into an old mine where he discovers the frozen body of a US Army sergeant and mining expert Jake Hobart. Next to the frozen corpse is a newspaper from 1912 as well as some mining tools from the early part of the 20th Century. Using a radiation meter, the spy discovers that what he seeks, an extremely rare mineral named byzanium was there but has been mined out leaving only traces. He is then chased and shot by Soviet forces but rescued at the last moment by Dirk Pitt (Richard Jordan) a former U.S. Navy officer and a clandestine operator.