Bond's house is blown up, and he (implicitly) agrees to the assignment. While they're pitching the idea of coming out of retirement to Bond, they're attacked.
It seems that someone has been trying to wipe out as many secret agents as they can. A group of older men, representing the secret agencies of the US, the UK, Russia and France, are on their way to the real Bond's home to ask for his assistance. Casino Royale has it that the Bond we know from other films is a decoy. This Bond is quite different than the Bond we know-he is almost chaste, he's a homebody, he dedicates each evening's twilight to playing Debussy on the piano, and so on. The real Bond (David Niven) went into retirement when his skills were at their peak.
The story, which is very loosely based on Ian Fleming's James Bond novel Casino Royale (published in 1953-it's the first Bond novel), is a spoof of the typical adventure featuring the infamous secret agent. Most threads are just completely abandoned after awhile. There is little in the way of overarching plot.
And with at least five directors and at least ten writers, it's not difficult to see why. The problem arose in putting all of it together. Many of its segments are funny it's even occasionally hilarious. There are beautiful, often provocatively dressed or relatively undressed women everywhere you look. Casino Royale has some outstanding elements.
