Thomas’ Adventures of The Wild Thornberrys Movie is an upcoming Thomas/Paramount crossover to be created by Stuingtion.
The film begins with 12-year-old Eliza Thornberry playing with a family of cheetahs in East Africa, where her parents Nigel and Marianne Thornberry work as roving wildlife photographers for a television nature show. Eliza has the magical ability to talk and communicate with wild animals. Eliza also rides on the back of a female elephant named Phaedra throughout the jungle. The cheetah mother, Akela, has left Eliza in charge of her cubs; however, Eliza strays beyond the security of the area, and one of the cheetah cubs, Tally, is kidnapped by poachers. Eliza's persistent efforts to rescue the cub lead her British grandmother Cordelia, who is visiting them, to send her off to an English boarding school, fearing that Eliza is constantly endangering herself in Africa and will be much safer in England much to Debbie's dismay that Eliza had to go instead of her. Darwin, Eliza's "pet" chimpanzee, smuggles himself into her luggage and travels to school with her. After a chaotic food fight at a dinner Darwin attends, he is discovered and gets Eliza in trouble. The headmistress tells Eliza that her grandmother will be disappointed in her. Eliza is still guilt ridden for causing Tally to be taken away by poachers.
After having a dream in which Shaman Mnyambo, the person who gave Eliza her power, tells her to save Tally, Eliza persuades her roommate Sarah Wellington to help her and Darwin get back to Nairobi. While on a train to their family's camp, the duo notice an injured rhino outside the train and get off to help it. Eliza speaks with the rhino who tells her that he was shot by the river. They are assisted by a young couple, Sloan and Bree Blackburn, supposedly animal conservationists, but as they attempt to save the rhino, Eliza discovers the same knife carried by the poacher who took Tally. After the rhino is taken away by a ranger, Eliza and Darwin continue to their camp.
Meanwhile, Eliza's elder sister Debbie, a materialistic girl who dislikes Africa, has been left alone by her parents to take care of her mischievous adopted brother Donnie near their recreational vehicle (the Comvee), while her parents film a huge herd of elephants as they make their way through the fictional Tempo Valley during a solar eclipse. She is visited first by both Cordelia and her grandfather Colonel Radcliffe Thornberry who are searching for Eliza. The morning after they arrive, Eliza and Darwin themselves appear to plot a course to where Tally was taken, and later leave with Donnie. Debbie demands to know why Eliza gave up a chance for a normal life in England. Eliza, Darwin, and Donnie lock Debbie in a cage and run into the jungle. While Debbie searches for them, she comes to a friendly native village where no one speaks English. After several failed attempts to get her motorcycle out of the mud in which it is stuck, she meets a teenage boy from the village named Boko who helps her to get the motorcycle out. The village members, worried that Debbie will get killed out in the wilderness, send Boko as her guide.
As Eliza, Donnie and Darwin trek through the forest, a gorilla informs them that people have built a fence across Tempo Valley. The trio later encounter Bree and Sloan again, and Eliza realizes that the poachers are after the elephants that will be traveling through the valley. The trio later find Tally in Bree and Sloan's RV, and realize that the couple are actually the poachers responsible for capturing the cheetah cub, shooting the rhino, and building the fence. The couple later capture them, and it is revealed that the fence is electrified, and that the poachers plan to stampede the elephants into it, which it will kill them. Sloan demands to know how she found about the rhino and the fence.
Debbie and Boko later encounter the RV while searching for Eliza and her friends. When Sloan and Bree go to investigate their arrival, Tally chews on the rope bounding Eliza to free her. She and Darwin then get into an argument. Eliza argues that she tried to do the right thing and thought Bree and Sloan were like her; however, Darwin argues that she always gets them into one trouble after another and he yells at her for using her powers poorly. Eliza ends the argument by yelling at Darwin to, for once in his life, be quiet, which upsets him. Meanwhile, Sloan takes Debbie hostage when Debbie comes to bring Eliza home, and threatens to throw her over a cliff unless Eliza tells him the truth about how she knew about their plan. Eliza has no choice but to admit she knows because of her ability to talk to animals. A storm begins, blowing Boko away while Eliza and the others escape from the poachers. Eliza finds that her powers are gone when she can no longer communicate with Darwin, and the group ends up drifting down the river on a log as the storm continues.
Later on, after the storm has stopped, Eliza tells Debbie the story of how she got her powers and that she had kept them a secret all this time. Debbie asks Eliza to prove it, but Eliza tells her she can't anymore because she told someone else about her gift, and now she can't even apologize to Darwin for their argument earlier. Debbie then realizes how much Eliza's powers meant to her and is amazed that she gave it up just to save her life, and the sisters reconcile their differences. They get to the pass, just in time for the eclipse, but Eliza is doubtful that she can save the elephants without her power. Debbie convinces her to try when she points out that Eliza was always willing to help animals before getting her power (although she quickly tries to get her to stop out of fear for her life).
As Bree and Sloan get their henchmen to detonate explosives in the valley to get the elephants to stampede, Eliza jumps onto Phaedra, and desperately tries to tell her to stop. She uses a necklace her father gave her before she left and hurls it at the electric fence, causing it to react and the elephants to subsequently stop. They begin to turn around but Bree and Sloan order their henchmen to fire off another round of explosives, making the elephants charge towards it again. Eliza remembers how elephant mothers tell their young which way to go; she taps the elephant behind its ear, causing her to stop right in front of the fence. The herd again stops, and begins to turn around, much to the poachers' anger. Sloan then swings in on a helicopter and grabs Eliza, throwing her into a river, but not before saying that she won't be there once he and Bree cut out the ivory tusks of the elephants. Fortunately, she is saved by Shaman Mnyambo, who tells her that she saved the day using not her powers but her heart. As a reward, he is willing to give Eliza her powers back.
Meanwhile, the elephants pull Bree and Sloan's helicopter out of the sky, and the two poachers are arrested by rangers contacted by the Thornberrys. Soon, Eliza, Debbie, and the others are then reunited with the rest of the Thornberrys, who have all been searching for them, and Eliza makes amends with Darwin. Boko then catches up with Debbie, who gives him her watch as a gift before returning to his village. Phaedra returns to Eliza to thank her for what she had done by returning her father's necklace to her.
Later on, the group returns to the savanna they were at during the beginning of the film, where Tally is reunited with his mother once again. Eliza also reveals to Debbie that although she got her power back, it was on condition that if Debbie tells anyone about it, she will turn into a baboon, much to her fury. She frightens a group of baboons that Nigel and Marianne are filming and one of them turns on the radio which plays Brandy, P. Diddy and Bow Wow's "Dance With Us". The Thornberrys and the baboons dance to the song together while the cheetahs play with each other on a hilltop overlooking the Thornberry's campsite.
- Willy, Dusty Crophopper, Bernard and Bianca, Jake, Blythe Baxter, Zoe Trent, Pepper Clark, Penny Ling, Vinnie Terrio, Sunil Nevla, Minka Mark, Russell Ferguson, and Mitzi guest star in this film.
- Percival C. McLeach, Joanna the Goanna, Ripslinger, Ned and Zed will work for Bree & Sloan in this film.