Grumpy Queen Uniqua wants to take a nap, but she can't do that with a big giant on the loose! Then she hires some clumsy wizards, Pablo and Tyrone, to get rid of her. They try several spells on Giant Tasha before they figure out a clever solution.
A sandy area is shown with a horse, a tree, and a bucket. Tasha's feet stomp down on the area. The camera zooms out, revealing that the sandy area is actually the sandbox filled with toys. Tasha repeatedly chants "Boom, boom!". She then looks towards the screen and greets the viewer. She introduces herself as Tasha the giant, a very large creature. Tasha begins singing Nobody's Bigger Than the Giant. The backyard transforms into a region filled with trees. Tasha sings a reprise of Nobody's Bigger Than the Giant.
Tasha spots a village far from the forest and begins walking slowly towards it. The camera moves to one of the houses in the small village, where wizards Pablo and Tyrone live. Pablo asks Tyrone if they can try a spell, but Tyrone reminds Pablo that it is difficult casting spells. The two sing It's Hard to Be A Wizard. Through song, they explain how they can never get spells right, and demonstrate how whenever they try a spell, it comes out wrong.
The two recieve a call from the village queen, Uniqua, through a glass ball. Uniqua tells the boys that she is trying to take her royal nap, but cannot sleep with the giant causing so much noise, and orders the wizards to get rid of the giant. Pablo and Tyrone tell her they will do so. Tyrone tells Pablo that they could use a spell to get from their house to Queen Uniqua's castle. They wave their wands and recite magic words. The spell brings them on top of the castle of Queen Uniqua on a pole. They are hung by the back of their robes.
The camera moves to Queen Uniqua inside the castle. Pablo and Tyrone arrive. Uniqua asks them why they took so long, but the wizards ignore the question. She orders the boys to get out of her castle and get ride of the giant. They dash out. Pablo tells Tyrone that it is a long walk from the village to the forest where the giant is, so the wizards use a flying spell, hoping it would cause them to fly into the forest. Instead, they fly around in circles away from the forest.
The wizards are brought outside of the queen's castle. Uniqua spots them and gives the boys a grouchy look. Pablo and Tyrone walk to the forest. By the time they arrive, they are exhausted. Tyrone sits down on a circular red item, which he claims to be a rock. The "rock" begins to move, revealing that the rock is actually the shoe of Tasha the giant. Pablo and Tyrone are petrified and try to run away from Tasha. Tasha is confused, thinking the wizards want to play tag, and yells to the boys that she will get them as she chases after them.
The wizards, singing the song I Know A Spell, want to transform Tasha into something other than a giant. Pablo suggests turning her into a sheep, so the wizards recite the magic words to a spell in which the giant turns into a sheep. But instead of turning into a sheep, Tasha falls asleep. The wizards are disappointed. Then the wizards try to make the giant disappear. They disappear instead. After they turn visible again, Tyrone suggests to make the giant go away, but instead, they go away to the North Pole. Tyrone tries to go back again, but instead, they are teleported to the moon. Pablo tries to go back, and they accidentally appear in Queen Uniqua's Castle.
Queen Uniqua is angry at the boys, so they quickly try to go back to the forest where they began. Finally, they end up landing in the giant's head. The wizards are scared and scream, causing the giant to wake up. The wizards lose their balance on the giant's head and fall into a pond. The wizards are disappointed, and the giant tries to grab the wizards. The wizards run for their lives, and the giant chases them as if they were playing tag. They try to bring horses with their magic, but instead, they turn into horses. The giant catches up with them and they run away as horses, neighing. Queen Uniqua spots the horses. She is very mad and tells the wizards to stop playing around and make the giant go away immediately, or she'll fire them.
The wizards obey and turn into wizards again. The giant catches up with them again, and now she is almost at the castle. Tyrone suggests to do the same size spell, even through it is the most difficult trick ever, and they manage to make two giant bubbles (which will make anything the same size as another being if you touch it). The giant sees the bubbles and she blows them toward the wizards cheerfully. The bubbles pop on the wizards, causing them to become giants!
The wizards are scared of the giant (even though they are all the same size). The giant tags them and they finally understand that the giant just wants to play tag with them. After Queen Uniqua scolds the wizards for turning themselves into giants, the wizards make her giant as well. The giant, the wizards, and the queen are happy that they got a spell right for the first time ever and they play tag while singing On Top of the World. Pablo's stomach growls and Tyrone suggests to have a snack at his house. The village transforms back into the backyard as the kids sing the end song. They enter Tyrone's house. Tasha opens the previously closed door and shouts "Yoo-hoo!".