- This article is about the episode. For the location, see The Heart of the Jungle (location).
"Tyrone is Tarzan, and so are Pablo and Austin! Each Tarzan has a different jungle skill, and they use them all to help Uniqua the brilliant scientist. Their quest, set to Gilbert and Sullivan-style operetta, is to help tiny Sherman the Worman find his jungle home. Will they succeed? Or will the treacherous jungle force them to bug off?"
At first, Tyrone is seen alone in the backyard yelling like Tarzan. He then greets the viewer and tells them that he is Tarzan the Animal Guy, who can talk to animals. He starts the song "I'm Tarzan". Pablo walks over as the song is still being sung, starting a second part explaining to the viewer that he is Tarzan the Very Strong. Austin then comes over to the two Tarzans, as Tyrone and Pablo explain in song that Austin is Tarzan Who Doesn't Say Too Much.
After the song ends, Uniqua (in a tan hat) walks over carrying something, and introduces herself as Professor Uniqua. Uniqua unfolds her hands, revealing a yellow worm-like creature called a Worman. His name is Sherman, he is sad because he lost and separated from the family. Uniqua cannot understand what Sherman is trying to say, because he can only speak in squeaks. Uniqua wants to know where his home is, to take him back there. Tyrone volunteers to listen to Sherman, because he is Tarzan the Animal Guy (who can talk to animals).
Tyrone tells the rest that he is from the heart of the jungle. So the foursome venture into the jungle as the backyard transforms into it.
Uniqua went through the jungle to find Sherman's home, but the Tarzans go after her saying that she needs someone to guide her and to protect her from dangerous things from the jungle, like Can't-See-Ums, insects so little that tickles people. Tarzans warn her about getting lost, the rain and quicksand. Uniqua thinks that jungles do not carry any quicksand, stating it as a science fact, and she is totally unaware of any muddy puddles.
They travel deep into the jungle. Uniqua and the Tarzans starts to sing the song "Where in the World". After the song, Uniqua was about to step in a watering hole. The Tarzans think that is quicksand, but with a stick they see that is not. Suddendly, a group of Can't-See-Ums run after the Tarzans, but Uniqua ward off them with Bug-Away Spray.
They all start to sing the song "Into the Thick of It" as they walk around in circles. Then the Tarzans realize that they have seen all the flowers, trees, and leaves before. Then they all realize that they have not gotten any closer to the jungle's heart. Uniqua uses a vine to swing, but her attempt was fruitless. Tyrone tells her that swinging on a vine only works, if she does the Tarzan yell. Her next attempt works, taking Tyrone's advice. The Tarzans follow, swinging off as they sing a reprise of "I'm Tarzan".
As they get closer to the heart of the jungle, they start to feel rain. Uniqua sings the song "It's Drizzling, It's Pouring". The rain gets heavier and they have to all sit in a leave so they can drift closer on the small stream the rain has created. While they were going by the stream, they saw that the leave was going to fall by a waterfall. Uniqua hooked umbrella to a vine and told the others they were going to jump to the bank. Pablo offers to help because he says that they need someone strong like him to do that. After they landed on the bank, Sherman says said that his house was nearby. They walk and see a lot of other Wormans crawling on leaves. One Worman spots Sherman, and all the Wormans scream to greet him. Uniqua and the Tarzans say goodbye to Sherman.
After they had taken Sherman home, Uniqua decides to go back to her laboratory and report their discovery. Austin spots a muddy puddle, Uniqua does not see it and steps into it. The Tarzans are alarmed and try to help Uniqua out of it as she sinks deeper into the puddle. They all see that it is quicksand. Austin uses the stick he finds to pull her out.
When she gets out of the quicksand, she thanked to the Tarzans for helping her and invites them all over to her house for a snack of pretzels after Austin's stomach growls. The entire cast returns to the backyard as the imaginary rainforest transforms back into its previous form. They sing the end song and enter Uniqua's house. Pablo, Tyrone, and Austin all open the previously closed door and they all yell like a Tarzan.