Act One

Off the coast of Africa, a small British ship is thrown about the sea. A Victorian Father, Mother and baby wash up on a tropical beach. As the father begins to construct a shelter, a family of apes enters. The apes, Kala and Kerchak, play with their own baby. The apes and humans are of separate worlds, but they share a common love of family. A leopard enters and swipes the apes' baby. Kala is devastated. Then, the leopard kills Father and Mother - but not before Mother puts her baby in a trunk for protection. Kala finds the human baby in the trunk alone and crying. She takes him in ("Two Worlds"). When Kerchak finds Kala with the human baby, he is not pleased. This human baby cannot replace their son; Kala knows this, but also knows that the baby needs a family. She names the baby Tarzan. Kala comforts a crying Tarzan, promising she'll always be here for him ("You'll Be In My Heart").

Ten years pass and Tarzan is the odd man out amongst the other ape children. A group of apes are picking on him when Terk comes to his rescue. Tarzan says he can take care of himself, but Terk points out that they both have special skills and can help each other - Terk can save Tarzan from the bullies, and Tarzan can help Terk pick fruit from a high tree. Tarzan isn't sure how he benefits in this deal, but Terk claims he has a lot to teach Tarzan ("Who Better Than Me?").

Tarzan makes a fruit picker from a stick and a stone, and is quite pleased with himself. Kerchak sees Tarzan threaten the apes with this 'weapon' and leads him deep into the jungle. Kerchak believes the only way to protect his true ape family is to abandon Tarzan in the jungle ("No Other Way"). Kala is very distraught by Kerchak's decision, but he insists that Tarzan will hurt them when he becomes a man.

Alone in the jungle, Tarzan is confused and hurt by the rejection from his father ("I Need To Know"). Kala finds him trying to put mud on his skin to be more like an ape. She insists that he is no different from her, but he protests. She points out that they both have two hands and a heart - they are the same. However, they have to live away from the group for a while. Tarzan vows to be the best ape ever. As Tarzan and Terk grow, Tarzan gains strength and ingenuity. Kala watches as they grow from boys to adults ("Son Of Man"). Kala goes to visit Kerchak, who is not doing well without her. She tells him that Tarzan is working hard to please him, but Kerchak is still very worried for Kala alone in the jungle and for his family with the threat of a nearby human. Kala reassures Kerchak that she loves him despite his stubbornness and he asks her to come home, but insists she can't come home alone ("Sure As Sun Turns To Moon").

In the jungle, Tarzan and Terk try to build a leopard trap; Tarzan's ability to tie knots allows him to build the trap, and he tries to teach Terk to tie knots but it doesn't work. As Terk and Tarzan bicker about Tarzan's new skill set, Terk gets caught in the trap. Just then, the leopard arrives. Tarzan manages to spear and kill the leopard, which he presents to Kerchak. Satisfied that Tarzan is not a threat to his family, Kerchak welcomes him back home. At that moment, a gunshot is heard. Kerchak knows what this means and ushers the family back home away from the gunshot, but Tarzan disobeys and goes in the direction of the noise.