The book focuses on a fictional MiG-31 Firefox aircraft supposedly developed by the USSR during the Cold War. It is not to be confused with the real MiG 31 developed some time later.
The fictional Firefox includes various advanced capabilities; most notably a form of stealth technology which makes it completely undetectable to radar; it is capable of attaining speeds of Mach five or more; its weapons are controlled by the thought impulses of the pilot, allowing them to be very rapidly aimed and fired. Less emphasised but equally impressive is the aircraft's three thousand mile range.
Faced with an aircraft which will give the Soviet Union the ability to completely dominate the skies, the CIA and MI6 launch a mission to steal one of the two Firefox prototype aircraft. The first section of the book details how fighter pilot Mitchell Gant covertly travels to Russia. With the help of a network of dissidents and sympathisers he makes his way to the Bilyarsk air base on which the two prototype aircraft are being developed. With the assistance of some of the scientists working on the project he is able to penetrate the base and successfully steal a MiG-31. This section of the novel depicts such intelligence work as a grim, frightening and stressful experience, a marked contrast to the more adventurous "Bond-type" thrillers.
The second section of the book deals with Gant's flight. Here the novel is notable for its focus on military technology and tactics. First heading east towards the Ural, then north to the Barents Sea, Gant narrowly escapes a Soviet fighter plane and frigate, exchanging fire on both occasions. Touching down on an ice floe, a submarine serves as his refueling point, before he continues his flight towards friendly air space. There, he is scrambled by the second Firefox prototype, which was sent in pursuit. Gant decides the duel in his favor, and continues towards his home destination.