The Seeonee pack of wolves in the jungle head to their own family's lair when they hear Shere Khan, the tiger with the pronounced limp but passion for fighting coming close. Mother Wolf protects her four cubs but is amazed to see a little naked brown human cub running into the cave. He is the prey that the tiger is looking for. Quickly she decides to bring the boy into her family, naming him Mowgli, which means "little frog", Mother agrees to show him to the pack alongside her own cubs to be identified, so that they can be free to run and play without fear of being killed. At Circle Rock, Mowgli's right to be a member of the pack is questioned by Shere Khan who still feels that the boy belongs to him. The Law of the Jungle states that if there is a dispute, a cub needs to have two members of the pack that are not his mother or father speak for him. As Mother prepares to fight for her man-cub, Baloo, the old brown bear, speaks for him and promises to teach him the laws of the jungle. This is seconded by Bagheera, the black panther, who buys Mowgli's safety by offering up to the pack a fat bull that he has just killed. Mowgli is then accepted into the pack.
His childhood is not described in detail but we rejoin him in the jungle when he is eleven years old. Shere Khan again demands that Mowgli be given to him and a fight ensues; Shere Khan has alot of the younger wolves on his side and they depose Akela. However, Mowgli has fire that he has been tending, and knowing how much the animals fear fire, threatens Shere Khan with it, and then orders that they leave Akela safe. Hugging his wolf family, who ask him to return one day, he goes towards the nearest village to find his own people.
When he arrives, he is welcomed into the home of a couple who believe him to be their long-lost son who was taken from them as an infant by a tiger. Messua, the woman, decides he is not their missing boy, but a boy send by the Gods to make up for their son being taken away. She treats him like her own but Mowgli, used to living in the jungle, is not comfortable or at ease in a human home. He sleeps outside, one day feeling Gray Brother, one of his wolf siblings, waking him, and choosing to sleep outside every night after that so they can meet. Gray Brother has learned that Shere Khan is still hunting Mowgli, and brings Akela to the village to try to help. Mowgli works every day in the fields herding buffalo, so they plan to divide up the herd to throw Shere Khan off the scent, then to make a big circle uphill to get ahead of the ravine, taking the bulls down into it and trapping Shere Khan between the cows and the bulls. Shere Khan takes the bait and is trampled. When he is dead, Mowgli starts to skin him with his knife, but having come searching for his buffalo, the Village Chief, Buldeo, realizes that there was a price on the head of this tiger who has been killing villagers, and demands the skin for himself so that he can claim the reward. Mowgli tells Akela that Buldeo is threatening him so Akela states the chief down. With the skin laid over the Council Rock, Akela is leader again. Buldeo, having convinced the entire village that Mowgli is one with wolves, declares him to be a sorcerer and Mowgli is banished from the village.
Buldeo leads a group of hunters into the jungle to try to kill Mowgli, who in the meantime has returned to the village to find Mussa and her husband bound and gagged and imprisoned in their home. He seems advice from Hathi the wise old elephant who starts to put the word out that the best food and best kill is available down by the village. With the help of Wolf Mother and Father, Mowgli frees Mussa and her husband, telling them to flee to the next village. After they have left, the jungle dwellers start to close in on the village in an effort to make the villagers move away. Hathi and his four sons eat all of the stored seed corn and this finally forces the starving humans to leave the village. Hathi barrels through buildings until nothing is left standing and in a few short months the jungle has grown over the land where the village used to be.
Having returned to the jungle stronger, and slightly feared, Mowgli is recognized as Master of the Jungle. One of his favorite friends is Kaa, the giant python, who saved his life After their customary play-wrestle they go back to the scene of Ka's life saving heroics and meet a huge, elderly white cobra who las lived underground for so long that he does not realize the jungle has taken over the old palaces of the Raj that he used to serve. He is the Warden of the King's Treasure and he allows them to take ownership of it, but only whilst they are in his lair. He threatens to kill Mowgli but after they overpower him Ka and Mowgli realize his fangs have dried up and he is not a threat at all. Mowgli takes a jeweled elephant head-dress with him but the white cobra tells him it is cursed and death will follow it wherever it goes. Mowgli doesn't believe him at first but then when a hunter looking to steal the item from them winds up dead, followed by six others with a similar goal in mind, Mowgli realizes he was speaking the truth and returns the jeweled spike to him.
The story forwards to Mowgli's seventeenth year, when his parents pass away. He rolls a boulder in front of their family cave and sings his mourning song. Akela is now too old to hunt for himself so Mowgli hunts for him. The Seeonee pack grows stronger. One day a lone wolf who lives not in a pack but with his wife and children comes to their part of the jungle having been involved in an attack by the red dogs. They killed his cubs and wife and have almost slaughtered him. He asks for help from the Seeonee pack. Mowgli heads to where the dogs are to count them and devises a plan, along with Kaa, to draw them towards the river at twilight where the bees will swarm and attack them. There is a giant battle but Mowgli's plan puts the red dogs at a huge disadvantage as when they are climbing out of the river the wolves, who attack by biting the throat, are able to attack before the dogs are fully out of the water. Akela is not killed in battle but realizes it is time for him to die and before he sings his own mourning song he tells Mowgli to go back to man as he has paid his debt to the jungle. Mowgli does not want to leave and is puzzled by Akela's claim that "Mowgli will drive Mowgli out of the jungle".
Spring comes and with it a strange, unfamiliar feeling in Mowgli's stomach that leaves him unable to fight properly and generally grumpy and depressed. He decides to undertake a Spring Running and begins a journey on foot that takes him to a village where again he sees Muessa and re-introduces himself to her. He is feverish and rests with her for a few days whilst she takes care of him.. As he is headed back to the jungle, Gray Brother finally answers Mowgli's call, and they trot back together as Mowgli breaks the news that he is going to rejoin the humans. He says farewell to his family - Baloo, Kaa and Bagheera, who tell him how my h they love him, and his wolf brothers, then sets off to live amongst men once more.
At the end of the book the reader learns the story of Rikki-Tikki-Tavi, a feisty and brave mongoose who is washed away from his parents during the rains and found himself living in a house where a family of three resided. He discovers a cobra and his wife who want the humans to leave so that they can have the bungalow to themselves when their children are born. Rikki boards the doors shut but hears a scraping noise that he realizes is the snakes coming in through the pipe work; they decide to hide in the bathroom but Rikki surprises the male cobra and disables him until the man comes to shoot the snake dead. The family are grateful to Rikki for saving their lives but he is mindful that the snake's wife will be even more determined to kill the family. He decides to smash all of her eggs, saving one to barter, which draws her away from the house and into her tunnel. Rikki follows, not knowing if he will make it out alive, but happily he does so after killing Nagaina, the female cobra. The family realize he has saved their lives three times now, and remain grateful to him but he is very humble, living with them and making sure the garden is kept free of snakes.