British and Russian ballistic nuclear submarines go missing. James Bond (Roger Moore) joins forces with a top KGB agent in the Bond-friendly form of Major Amasova (Barbara Bach) to investigate. As usual the trail leads to exotic locations, in this case Egypt where Bond and Amasova first encounter the man mountain Jaws (Richard Kiel) who has a mouthful of iron.
Bond and Amasova soon discover that mega rich industrialist Stromberg (Curd Jürgens) is somehow behind the plot, he is obsessed with creating a new society living under the seas. Bond wonders why has he got a new gigantic oil tanker with a curious bow which looks like it could open. Why the tanker looks big enough to be able to store two large submarines...
It is completely over the top of course. The gadgety and gimmicks are dialled up to the max. The film includes one of Bond's most iconic cars, the Lotus that could become a submarine. So many British boys (including myself of course) in the late 70s / early 80s had model versions.