With the arrival of spring, Mole loses patience with spring cleaning (“Spring”). He leaves his underground home for the river, where he meets Rat (a water vole), who spends all his days on the river. Rat takes Mole for a ride in his rowing boat (“Messing About in a Boat”). After this, he shares his picnic and an enduring friendship is born. Mrs. Otter gate crashes the friend’s picnic looking for her daughter Portia, who often wanders off in search of food. Rat and Mrs Otter warn Mole about the inhabitants of the Wild Wood and tell him of wise but solitary Badger who lives there. Mr. Toad is rich, jovial, friendly and kind-hearted, but aimless and conceited; he regularly becomes obsessed with current fads, only to abandon them abruptly. His current fad is boating, and he speeds by the picnic on a wager-boat (“Speed is of the Essence”).

The swallows arrive to herald the beginning of summer (“One Swallow Does Not a Summer Make”). Mole and Rat visit Toad Hall at Mr. Toad’s invitation. Having recently given up boating, Mr. Toad’s current craze is his horse-drawn caravan, which he invites the reluctant Rat and willing Mole to join him on (“The Open Road”). Parked at the roadside for an overnight stop, a passing motor carscares the horse, flipping over the caravan. Although Rat and Mole are upset, Mr. Toad becomes infatuated with motor cars. In his new racer, he terrorises his neighbours, particularly a family of nervous Hedgehogs (“The Hedgehog’s Nightmare”). The animals are both fascinated and dismayed about the new craze, which he enthuses about before crashing his car (“The Amazing Mr Toad”).

Autumn draws near. Determined to save Mr Toad from himself, Mole insists Rat and he venture into the Wild Wood to call on the support of Badger. When Rat refuses, Mole ventures on the scary road alone. Pursued by the Chief Weasel and his Wild Wooders, Mole only escapes when Rat has a change of heart (“The Wild Wooders”). However, the two become lost as the piles of leaves obscure the path (“Autumn”). When Mole injures himself on a boot scraper, Rat realises they have accidentally stumbled on Badger’s doorstep. As Badger invites them in, Chief Weasel tells his gang of Wild Wooders of his plot to steal Toad Hall so they can live the good-life. Portia, still looking for food, is kidnapped by the gang (“The Wild Wooders Reprise”).

Inside Badger’s house, Mole and Rat convince Badger to come to Mr. Toad’s aid (“A Friend is Still a Friend”). The trio arrive at Toad Hall to find that Mr. Toad has ordered a new car after his crash and decide to guard him in his bedroom until he learns some sense. Mrs Otter arrives, begging the friends to help her find Portia. Mole guards Mr Toad whilst Rat and Badger join the search. Feigning illness, Mr. Toad escapes Toad Hall, and steals a beautiful new car (“Toad’s Escape”). However, the car owner and police catch him in the act (“Stop Thief”).

Arrested for his theft, a court scene takes place with the Wild Wooders as the jury, making sure that Mr Toad is imprisoned so they can take over Toad Hall. Without showing much remorse, Toad recalls what happened in his grandiose manner while Rat, Mole and Badger try and convince him to show some remorse for his crime. The scene ends with Mr. Toad being sentenced to twenty years in jail, to his dismay (“As if in a Dream”).

With Toad in prison, the Wild Wooders have taken over Toad Hall and are fattening up Portia for a feast to come (“We’re Taking Over the Hall”). In prison, Mr Toad gains the sympathy of the Gaoler’s Daughter, who helps him to escape disguised as a washerwoman (“To Be a Woman”). Walking through the Wood, Rat and Mole discuss the imprisonment of their friend when they come across Mole’s home. Having realised that Mole hasn’t returned since the day he left his Spring cleaning, the friends have a humble feast, while Mole speaks fondly of his home (“A Place to Come Back To”). After this, some wassailing mice visit as is familiar to Mole, wishing well to the animals of the forest (“The Wassailing Mice”). As the song ends, Badger bursts in to inform Rat and Mole that Mr Toad has escaped prison. Knowing the Wild Wooders will torture and kill Toad if he attempts to enter Toad Hall, the trio set out to find him first.

Mr. Toad, pursued by the police, begins his escape. He boards a railway engine manned by a sympathetic driver. As the law catches up, Toad is kicked off the train, and, still disguised as a washerwoman, comes across a horse-drawn barge. The barge’s owner gives Toad a lift in exchange for Mr Toad’s services as a washerwoman. After botching the wash, Mr Toad gets into a fight with the barge-woman, and gets thrown overboard. Soaked, Mr Toad flags down a passing car, which happens to be the one he stole earlier. The car owner, not recognising Mr Toad in his disguise, permits him to drive the car. Once behind the wheel, he is possessed by his former passion and drives furiously. He reveals his identity to the car owner, and in the ensuing struggle, the car crashes (“The Greatest Great Escape”).

Badger discovers Toad at the doors of Toad Hall. Badger and friends tell Mr Toad that Toad Hall has been taken over by weasels and stoats from the Wild Wood and even worse, that Portia is trapped inside. After Mole convinces two guards that an attack on the Hall is imminent, Badger announces that he knows of a secret tunnel into Toad Hall through which the enemies may be attacked (“Hush!”). Badger, Mrs Otter, Rat, Mole and Mr Toad enter via the tunnel and pounce upon the unsuspecting Wild Wooders who are holding a celebratory party and about to cook Portia (“The Fight”). The friends celebrate their victory over the intruders. It’s spring once again, and the animals are working hard, while Rat and Mole quite happily row on the river together – they are both content in having one another’s company over the adventures Toad has. Mr Toad holds a party to mark his return, but his big entrance on an airplane (or, in some productions, on a jet pack) indicates that he hasn’t changed his ways at all (“Finale”).