The commvee's fuel pump breaks down and leaves the Thornberrys stranded in an African desert. A map reveals a nearby town 17 miles away and Nigel takes off on foot to find a new one. Things get bad when Marianne discovers their water tank has burst and they are almost out of water. Eliza and Darwin attempt to find water and run into a herd of Gemsbok and other animals near a dried up water hole. They are waiting for the rainmaker to bring rain and they think Eliza can talk to him. She gets caught up in their story and decides to play rainmaker herself.
The Thornberrys are in India when Eliza and Darwing are seen playing together by Kip and Biederman. They capture Darwin and sell him to a Rajah who is looking for a new chimp act to entertain his court. Eliza frantically searches for the missing Darwin and follows a trail of kumquats Darwin left to the Rajah's palace. Entry to the palace is forbidden and she will have to rely on her wits to sneak inside and rescue Darwin.
Eliza finds an animal hero in a giraffe who can see great distances with his height and warn others of approaching danger. However, to Eliza's dismay, the giraffe skips out on the animals for his own needs. O
Eliza frees a Hyena, but since it never lived in the wild it doesn't know how to survive. Eliza attempts to teach it, but it seems hopeless until a wild boar threatens them and the hyena's natural instincts take over.
Darwin brings Eliza to a chimpanzee compound. When Eliza is not being subservient to the hierarchy, Darwin gets in hot water with the leader. Only after a threatening fire starts does Eliza realize the necessary hierarchy for jungle survival.
The Thornberrys meet the Fensterkopfs, who make false documentaries. The Fensterkopf's kid lies to Eliza and gets them stuck on a cliff. After the families barely escape an avalanche, the value of truth is learned by all.
The Thornberry's trek their way up into the snow-capped Himalayan mountains to capture some rare footage of the local snow-leopards. However, something eerie looms in the distance. Eliza sets out to discover the secret of the ancient "Yeti!"
The Thornberrys are at the Yasuni National Preserve in South America near the Gallapagos Islands. They are there to see Lonesome Jake the last Tortoise of his species. Eliza feels terrible that he is the last one and is determined to search out a female...she asks the local animals and hears of one that lives in a volcano on the Gallapagos. It's a female named Samantha and they bring it back to Jake but Eliza's interfering matchmaking ways cause more harm than good. Love is also in the air for Donnie who finds a jungle girl who is his perfect match.
Eliza pulls the wrong lever and catapults the commvee to the bottom of the deeper waters of Australia! She is soon forced to don scuba gear and enlist the help of an army of dugongs in order to rescue her dad!
The Thornberrys are on the Russian peninsula of Kamchatka to film the Stellar Sea Eagle. Nigel and Marianne take off to film via helicopter while Eliza and Darwin explore. They meet up with a friendly group of Sea Otters and start playing together when an oil tanker comes into the area. To make matters worse Kip and Biedermann rupture the tanker and start an oil spill. Eliza takes it upon herself to save the otters. But when the oil catches fire who will save her?
Eliza goes through desperate measures to help animals survive during these tough times along the Skeleton Coast. However, the price she pays for her good-will intentions will soon cost her family's entire holiday cheer, including their Christmas dinner!
When the Thornberrys visit Nigel's friend Jomo, they search for an elephant, Rebecca, that Nigel saved twenty years ago. As the family attends to an elephant stuck in a mudhole, Eliza bonds with Rebecca, only to learn that she is old and ready to die.
When Eliza tries to swim with the humpback whales, Darwin's clumsiness leads to an accident that causes the whales to stop their ritual singing. When Eliza tries to set things right, she is arrested for violating the Marine Mammal Protection Act.
The Thornberrys are in the Philipines to find the Angler Fish. While Nigel and Eliza travel the river to find it Debbie and Marianne stay behind to study for Debbie's final. While looking for the fish Nigel is stung by a poisonous fish and Eliza must go into a dark, mysterious bog to get the antitoxin.
When Eliza meets a group of temple monkeys, they con her into bringing all of her family's food. While Darwin tries to convince her otherwise, Eliza realizes that she's been duped and learns the value of Darwin's friendship.
The Thornberrys visit a cattle ranch in Argentina where Marianne's old high school buddy,Gabriella, lives. Eliza is also looking forward to meeting her pen pal Miguel for the first time. While Marianne and Gabriella reminisce about old times Debbie develops a crush on the foreman Antonio. They all go out on a cattle drive where Eliza discovers that Miguel is not quite the gaucho he has led everyone to believe.
Eliza and a Chinese girl, Arioka, secretly switch places so Eliza can ride across the desert on camels and Arioka can ride in the Commvee, but Arioka's parents change their plans and Eliza must figure a way ro get them back to the Thornberrys.