Mole has been spring-cleaning his small underground home all morning. Suddenly, seemingly for no reason, Mole throws down his broom and whitewash and scrabbles his way to the surface. He trots along until he comes to a river, the first he’s ever seen. There, he meets Rat, who lives in a home built into the riverbank. Rat invites Mole to go on a picnic with him, so they take Rat’s boat down the river. Mole immediately loves everything about boating and life on the riverbank. On the way back after the picnic, he becomes jealous—he wants to row. When Rat refuses to let Mole row, Mole snatches the oars and promptly capsizes the boat. Rat good-naturedly puts the boat back together, takes Mole back home with him, and invites him to stay for a while. Mole agrees.
Over the next few months, Mole learns a lot about boating and river life. One day, he asks Rat to take him to meet Toad, who’s wealthy and conceited. Toad has a reputation for picking up expensive hobbies and then moving onto something new when the hobby proves too difficult. Toad’s newest hobby is traveling in a caravan—and he expects Mole and Rat to go with him on his first adventure. Several days into the journey, a car races up behind the caravan, scaring the horse so badly that the horse dumps the caravan into the ditch. But Toad doesn’t care about caravans anymore; he only cares about cars.
Mole has heard about Mr. Badger but hasn’t met him. Since Rat won’t take Mole to meet Badger, Mole decides to venture into the Wild Wood one winter day to call on Badger. Mole is soon lost and terrified—there are faces and odd sounds everywhere. When Rat realizes where Mole went, he tracks Mole into the wood and finds him in a hollow tree. The two rest for a while, during which time it starts to snow. They wander around, trying to get home, but end up discovering Badger’s front door by accident. Badger ushers them in, feeds them, and invites them to stay the night. They also decide that since Toad has now crashed seven cars, they’ll stage an intervention in the spring. In the morning, Otter arrives and walks Mole and Rat home.
Not long after, when Mole and Rat are out late, Mole suddenly senses his former underground home calling for him. Rat refuses to stop until Mole begins to sob. They return to Mole’s house, clean it up a bit, and then young fieldmice singing Christmas carols stop by. With Rat’s help, Mole serves the fieldmice a meal and enjoys a lovely evening in his former home. But he realizes that while it’s nice to know he can always come back, he now belongs on the river.
Interspersed between the next several chapters are short anecdotes. In one, Otter’s son, Portly, has gone missing. Worried for the young otter’s safety, Mole and Rat go out looking for him at night—and they follow the sound of pipes to a beautiful island, where they encounter the demigod Pan protecting Portly. They worship the demigod, and Pan causes the friends to forget they ever saw this “Vision.” Rat and Mole take Portly home to Otter. In another, a wayfarer rat shares a picnic with Rat and tells him all about his exciting travels between warm southern ports. Rat is ready to head south, but Mole convinces Rat not to leave.
Back in the main story, it’s now spring. Badger calls on Rat and insists it’s time for their intervention; Toad has just ordered a new car. Badger, Rat, and Mole head for Toad Hall, where they stop Toad from getting in his new car. When Toad refuses to promise to never touch a car again, Badger announces that he, Rat, and Mole will guard Toad in the house until Toad recovers. Toad seems to be improving when, one day, he tricks Rat into leaving him unattended and sneaks out. Before long, he encounters an unattended car at an inn and steals it. When he’s apprehended soon after, the magistrate sentences him to 20 years in prison.
Prison is extremely depressing for Toad, but things start to look up when the gaoler’s daughter takes over guarding him. She loves animals (as pets)—and as she and Toad get to know each other, she starts to feel sorry for him. She helps Toad switch clothes with her aunt, who’s a washerwoman, and sneak out of prison in disguise. This works perfectly for Toad until he’s trying to buy a ticket at the train station and realizes he has no pockets and no money in his cotton dress. The engine driver believes Toad’s disguise and offers to take Toad in the engine in exchange for some washing. But soon, he notices a train following them carrying policemen and detectives, and Toad tells the engine driver the truth about his identity. The engine driver helps Toad sneak off the train into the woods.
Toad spends a cold night in the woods and starts walking the next morning. He soon meets a woman on a barge, who offers to give him a ride when she hears Toad’s sorrowful tale (he lies that he’s looking for his married daughter, who’s in trouble, and left washing and naughty young children at home). When Toad boasts that he loves laundry, the woman asks Toad to do some of her laundry to compensate her for the ride. But Toad has never done laundry in his life, and it shows. When the woman realizes that Toad is a toad and not a human woman, she throws Toad into the river. In retaliation, Toad steals the woman’s horse and gallops away. A few hours later, Toad sells the horse to a “gipsy” man for a few shillings and breakfast.
Toad feels so smart and proud of himself for getting the better of the barge woman that he starts to sing a song about how great he is. He feels even better when he hears a car coming; he can ask for a ride. But he slumps to the ground when he sees the car is the same one he stole. The drivers, though, don’t recognize him, and pick Toad up—they believe he’s a fainted washerwoman. Toad asks if he can sit in the front and then asks to drive. The drivers let him. Exhilarated and angry, Toad reveals his identity and drives the car into a pond when the drivers try to grab him. He runs away unscathed, proud of himself, but breaks into a run when he realizes a driver and some policemen are chasing him. Toad fears he’ll be put back in prison. Suddenly, he falls right into the river.
Lucky for Toad, he manages to grab the bank right at Rat’s doorstep. Rat helps Toad inside, lends him a suit, and feeds him, but he refuses to listen to Toad’s exaggerated story of escaping from jail. He tries to guilt Toad into changing his behavior, and at first it seems to work—until Rat reveals that Toad can’t go home, since stoats, weasels, and ferrets have taken over Toad Hall. Enraged, Toad goes to Toad Hall, first on foot and then in Rat’s boat, to try to get his home back. A ferret shoots at him the first time he tries, and the second, stoats throw a rock in the boat, sinking it. When Rat remarks that Toad is a terrible friend since he ruins his friends’ belongings, Toad feels awful.
Not long after this, Badger and Mole arrive—they’ve been camping and trying to keep an eye on Toad Hall. Badger reveals that there’s a secret underground passage from the riverbank to Toad Hall; they can sneak in. Preparations begin the next day, and Mole distinguishes himself by dressing in Toad’s washerwoman clothes, going to Toad Hall, and telling a guard that hundreds of animals are going to storm the hall later. He also learns that the Chief Weasel is holding a banquet later. Toad is jealous, both that Mole did something so heroic and that Badger praises Mole so much.
After dark, Badger leads his friends through the underground passage. He scolds Toad for not taking things seriously enough, but the friends’ plan ultimately works. They burst out of the butler’s closet, taking the weasels and stoats by surprise, and take back the house in minutes. Mole is given extra responsibility and extra praise, which again makes Toad jealous.
Toad sleeps in late the next morning, as usual. When he wakes, Badger says that Toad has to write invitations and invite animals to come to a banquet to celebrate his return home. Toad is angry about having to spend a beautiful day inside writing letters, but he feels better when he comes up with a program of songs and speeches (by him, about him) that he includes in each invitation. But Toad’s friends discover this and tell him that under no circumstances can he sing or give speeches tonight. He must turn over a new leaf. Toad promises to do so and runs to his bedroom, sobbing.
In his room, Toad arranges chairs as for an audience and sings a song he wrote about his homecoming. Then, he combs his hair and goes downstairs to greet his guests. All night, Toad is quiet, polite, and modest—he’s a totally new toad. After this night, Toad sends the gaoler’s daughter a necklace and compensates both the engine driver and the barge woman for their help. Toad, Mole, Rat, and Badger continue to live peaceful, contended lives, and other animals greet and admire the four gentleman as they stroll through the Wild Wood.
