Natalie Babbitt's fantasy novel Tuck Everlasting tells the story of 10 year old Winnie Foster, who meets a boy names Jesse Tuck who claims to be 104 years old. Jesse reveals that him, and his whole family, gained immortality from drinking from a magical spring. Winnie learns to love the Tucks, and is forced with the hardest decision she'll ever have to make: a normal life, or one of immortality with Jesse.
Eleven-year-old Winnie Foster is tired of her family and is thinking of running away from her home in rural Tree-gap, New Hampshire. One day, while in a wooded area her family owns, she sees a boy about the age of 17 drinking from a spring. He tells her that his name is Jesse Tuck and forbids her from drinking the water. Soon after, his brother, Miles, and mother, Mae, take her away with them and explain what is happening and why they did what they did. All the while, they are being pursued by a man in a yellow suit who had approached the Fosters asking questions about their land the day before.
The Tucks explain to Winnie that the spring is magical and grants eternal life to anyone who drinks its water. They discovered its effects by accident after heading to the Treegap area to try and build a new life for themselves. In the process, Miles had to deal with his wife leaving him and taking their children with her. They have been living in seclusion outside of Tree-gap for years, reuniting every ten years and drinking from the spring. Winnie grows particularly fond of Jesse and his father, Angus Tuck, who teaches her about the life cycle that they are no longer a part of and why she must keep their secret.
Meanwhile, the man in the yellow suit has been pursuing the Tucks. Once he discovers Winnie has been taken by them and overhears their whole conversation, he steals their horse and rides it back to the Foster homestead. After he informs her family of Winnie's whereabouts, they dispatch him and the local constable to return her. However, he breaks away and rides ahead of the constable because he has an ulterior motive for finding Winnie.
When the man in the yellow suit arrives at the Tucks' farm he informs them that he has been searching for them for years. Miles' wife and children had come to live with his family when he was a boy and he heard rumors of their secret. He intensified his search within the previous six months. He then informs the angry family that he told the Fosters where Winnie was and that he has received a bounty in exchange for her safe return: the wooded area, and with it the spring.
The man in the yellow suit then further angers the Tucks when he tells them that he plans to gather the water from the spring and sell it to the public. When they angrily refuse his offer to be partners in the venture because they desire privacy over the money, he then declares he does not need their permission to sell the water and begins to take Winnie away. He tells the Tucks that if they will not be his examples then she will. He says that a child would be a better example and there is nothing they can do to stop him. Mae, in a last-ditch effort to put an end to the confrontation, grabs her husband's shotgun and begins wielding it like a club. The man in the yellow suit tries to make a break for it and Miles tries to get his mother to stop what she is doing. Neither man is successful. Mae pistol-whips the man in the yellow suit. The stock of the gun strikes the man in the yellow suit in the back of the head with enough force that his skull is fractured. This all happens just as the constable arrives and Mae is arrested on the spot. Later that evening, the man in the yellow suit succumbs to his injury and Mae is condemned to be hanged.
They realize that the secret will be revealed once Mae is hanged so her family and Winnie go to the jail and spring her from her cell. Then Winnie takes her place so the Tucks can safely get away. Although they are reunited, there is no more reason for them to be in Tree-gap as Mae is now a fugitive from justice. Before departing, Jesse gives Winnie a bottle of the special water so she might drink it when she turns 17 and follow them and marry him. She gives it consideration but decides not to and pours it onto a toad because she thinks that if she changes her mind then she can go to the spring to get more.
Many years later Mae and Angus return to Tree-gap, New Hampshire and find that it has changed a great deal. The wooded area is gone and so is their spring. The town has become a typical suburban metropolis. While there, they happen to visit a cemetery where they discover what happened to Winnie. She went on to marry and had two children named Jack and Anne; she had died two years before in 1948. Though Angus Tuck is saddened by this, he also praises Winnie for choosing not to drink the water. They come across a toad near her grave but they are unaware that it is the same one that she had poured water on years before.