In the hope of winning the annual horse race, Eliza trades in her bungling trotter for a swift Thoroughbred.

Eliza's cousin Tyler Tucker joins the Thornberrys for a four-week tour from Africa to the Amazon in search of exotic, endangered and mysterious animals.

Location: Masai Steppe, TanzaniaEliza and Tyler work together to help an aspiring Masai warrior earn the respect of his elders.

Location: The Siwa Oasis, EgyptEliza challenges Tyler to lead the group to safety after they land in an underground burial chamber.

Location: Zanzibar, TanzaniaDebbie and Tyler mistakenly trade the commvee for a dress at an island marketplace; Marianne and Nigel explore the Ngorongoro Crater.

Location: Mt. KilimanjaroTo celebrate his 13th birthday, Tyler and Eliza visit a pair of elephants in the African savanna.

Location: Ha Long Bay, VietnamEliza encounters a mysterious creature while shooting a film with Nigel about manta rays.

Location: Ankarana, MadagascarThe Thornberrys are preparing for Thanksgiving in Madagascar when Grandma Sophie calls, inviting them home for the holiday. When Nigel and Marianne explain that they can't go home until they get footage of a fossa for The Foundation, Debbie throws a tantrum. Will the girls, Donnie, and Darwin go to the states on their own when tradition has always had the Thornberry clan together on Thanksgiving?

Location: Quito, EcuadorBefore New Year's Eve, Debbie accidentally hurts fer father's feelings, and joins a couple of eccentric, 30's-era volcano chasers, Mitzi and Merrick Dash. Eliza goes after her to reclaim her friend, Santusa the Llama, and they all encounter a mudslide when the volcano erupts.

Location: BhutanA trip to Bhutan, finds Marianne and Debbie out in the cold, and Eliza and Darwin on the run from the border police.

Location: Lake Baikal, SiberiaWhen Eliza and Debbie slack off on their chores, they all suffer for it when they fail to prepare of an oncoming storm. Will the Thornberrys survive a flash flood, help some beavers build their dam and keep the Comvee from sinking?

Location: Kakadu National Park, Northern Territory, AustraliaThe Thornberrys meet an Australian family named the Gibsons when the Comvee runs out of gas. Eliza makes friends with the youngest member of the family named Bethany, who is in a wheelchair from cerebal palsy. The girls go land sailing and Bethany helps Eliza escape from a crocodile, but then get in an arguement when Bethany thinks Eliza is feeling sorry for her being disabled. Will the two new friends find a way to make up? Meanwhile, Nigel and Marianne play the Gibsons in a very competitive game of Tricky Trivia.

Location: Alice Springs, AustraliaDebbie is finally going to meet her e-mail friend in person and she is determined to make a good impression. Meanwhile, Eliza is having strange pains in her stomach and ends up stranded on top of a small mountain as Donnie gets attacked by a giant eagle. Just a typical Valentine's Day for the Thornberrys in Australia.

Location: Shark Bay, AustraliaNigel and Marianne are on a dangerous assignment to film some tiger sharks while Eliza goes swimming with some dolphins. Meanwhile, Debbie gets dumped by her e-mail boyfriend Sven. When the kids take a boat out with the dolphins to swim in the deep sea, they may get some unexpected visitors.

Location: Okavango Swamp, BotswanaIt's April Fools day, and The Thornberrys are trying to outdo each other by way of April Fool's jokes. At first it's a lot of fun, but when Tyler and Eliza encounter some quicksand and a lion, will they learn not to cry wolf? Meanwhile, Nigel coaches Debbie for her Physical Education courses.

Eliza and Debbie embark on a dangerous trek in search of precious gemstones.

Mt. Fuji, JapanGrandpa Frank marks the occasion of his 50th wedding anniversary by throwing caution to the wind and joining Eliza on a rigorous mountain climb.