The mood of Tuck Everlasting changes throughout the novel. It begins very somber and melancholy. When Winnie Foster is kidnapped by the Tuck family, she learns of their secret. Angus Tuck is tired of being "stuck on the wheel" of life. He even says that he was upset when he awoke, as he was having a dream about being in heaven. The oldest son, Myles, feels similar to Angus. He lost his wife and children after they discovered he wasn't aging. One may think eternal life would be a gift, but the Tuck family seems to evoke the sense that it is more of a curse than anything else. While everything is growing and changing around them, they are stuck right where they were eighty-seven years ago, when they drank from the spring.

The end of the novel shows a bit of a change, as Jesse Tuck hopes for Winnie to drink from the spring when she turns seventeen and go find him again so they can live together forever. When they leave Treegap after helping Mae escape from jail (for killing the man in the yellow suit), he tells Winnie to find him. The novel ends many years after, when Mae and Angus return to Treegap. They find Winnie's headstone in a cemetery, indicating her death. Angus is relieved to see her headstone, knowing she lived a long, healthy life. The mood here suggests tranquility.

The mood of Tuck Everlasting is one of triumph ! In Tuck Everlasting the human spirit prevails. The Tucks suffer a lot but are saved and Winnie goes back home a better person. The darkness period was when the Man in the Yellow Suit makes threatening demands on the Fosters and the Tucks, but the willpower of the Tucks to save the world from the dire consequences of eternal life overpower the evil the Man brings.