Left alone in the Louisiana swamp, Tefé Holland misses her mother and father. Meanwhile her friend Lady Jane is trying to help Swamp Thing find Tefé's mother Abby, leaving Tefé by herself. At first, she is pleased to be free of her parents' rules, but ultimately, being alone is boring for her. Knowing that all of those that she loves are gone, she feels unloved, and cries.
Suddenly, she hears a voice calling her name. It is a boy named Puck. He sympathizes with her loneliness, convincing her that her parents have neglected her. With little prompting, Puck convinces Tefé to join him on a journey to his home of Free Country, a place for children who have been abused by adults to live forever in paradise. By playing a game of One Potato, Two Potato, they create a portal to Free Country. Just as they pass through it, the Dead Boy Detectives arrive too late to stop Puck from taking Tefé away.
Puck shows Tefé all the wonderful places in Free Country, like a town made of candy, and another full of toys. In Toy Town, she encounters her long-lost Dollie, who acts as her companion and tour-guide. Puck and Dollie take Tefé to a petting zoo, where she meets Maxine Baker, a girl with powers like hers. While Tefé has access to The Green - a force which connects and pervades all plant life - Maxine has access to The Red, which connects and pervades all animal life.
Maxine joins the group, but wonders who takes care of all the animals and children in Free Country. In answer, Dollie takes them to meet Grandma, an old woman who looks after children who miss having someone to care for them. Grandma introduces the girls to all of the children she has taken in. Each one has a story of pain and suffering at the hands of adults, which prompted them to come to Free Country. Puck explains how Free Country began after the Children's Crusade, where the surviving children were sold to slavery, imprisonment, or brothels and escaped to Free Country. Puck reveals that he himself was one of those survivors.
Suddenly, a talking dish and spoon arrive to announce that a big meeting is being held at the story book castle. The children all go to the castle, where Princess Maya explains that Free Country is under threat from Thundermugg, King of the Gobble-You-Ups. She indicates that both Tefé and Maxine have abilities which can help them stop Thundermugg from using a stolen ruby to destroy Free Country. The girls agree to help, while Dolly, Puck, and some of Grandma's children volunteer to support them.
Deep in some dark woods, the children are attacked by some Gobble-You-Ups and bandersnatches. In the ensuing panic, Dollie is torn to shreds by the bandersnatches. Meanwhile, Puck and the other children are captured while Tefé and Maxine run. Dollie, barely alive, tells Tefé to save the others.
Elsewhere, Thundermugg brags to the captured children about his plans to convert Free Country into a dead land of swamps. He is interrupted by the appearance of Tefé, who accesses The Green and envelopes him in vines while the plants untie her friends. Thundermugg sets loose the bandersnatches, but Maxine easily calms them. Despite their apparent success, Thundermugg mocks the girls' efforts, claiming that he has already set Free Country's destruction in motion. Righteously enraged, Tefé accesses The Green again, attempting to recreate everything. However, she is not powerful enough to do it all alone. Maxine offers her help, and together they access both The Green and The Red to recreate all plant and animal life, thwarting Thundermugg's plan.
Back at the castle, the effort she put forth seems to have been so taxing on Tefé that she collapses. It is then revealed that the whole activity had been a test of their devotion and abilities, much to Maxine's disgust. Puck and his friends explain to her that Free Country really is in danger, because the coming influx of children threatens its sustainability.
Unfortunately, Tefé's condition is quickly worsening. Maxine attempts to heal her using The Red, but because Tefé is half plant, there is nothing she can do for her. Maxine concludes that if Tefé isn't returned to the real world, she will die because she is too far from The Green. Reluctantly, Puck agrees to return her to where he found her. Before leaving, though, Tefé asks Maxine if she will be coming too. Maxine declines, thinking there is more to know about Free Country.
Back in the swamp, Tefé is revived and happier, remembering that things will be alright, even if her mother is missing, because she is her daddy's little girl.
