The Chief Weasel discovers that Toad has a double: an actor, impersonator and con artist (in short, someone after his own heart) called Isambard Bilbone Toad. Together, they form a plan which involves the kidnapping of the real Toad and the acquisition of Toad Hall, all without the riverbankers noticing. Once this is done, Isambard continues to play the role of Toad in public, having perfected his voice and mannerisms. However, Badger, Rat and Mole cannot help noticing some slight oddities about their friend, particularly when he spreads slanderous remarks that the three have supposedly made about each other. Then, as if that were not strange enough, Toad breaks off his friendship with them, in favour of the weasels who are now sharing the Hall. Eventually, Badger’s keen observation leads them to realise the truth, and they must now rescue the real Toad before the weasels put an even more audacious plan into action and Toad becomes the weasel's slave forever.