BAST (Brotherhood of Anarchy and Secret Terror) plan to the World Leaders (of the time, so it's Gorbachev, Thatcher and George Bush) and then hold the World to ransom. Which leads to the question...How much were they expecting to get? Can't see many British people paying much to get Thatcher back in 1989... In fact John Major probably would have paid a pretty penny for them to have kept her (along with John Smith, the then Labour leader).
Anyway, the book is standard Gardner Bond fare. If you're read any of the other Bond books by John Gardner then you'll know what to expect and if you haven't then I suggest that this isn't the one to start with.
Still, good fun.