In the beginning, Max and PJ hid in the bushes from Pistol (as the ringmaster with a whip) because they didn't want to play Circus with her. Because of that, she went to ask her dad to play. Pete unwittingly agreed to the proposal, but he couldn't take his affirmation back and must play with her, since she whined at his refusal (so that Peg will keep an eye on him). So then, Pistol sat on Pete (horseback) while he was forced to scamper around the house. Fortunately, Pete saw an ad on the newspaper of a circus. He told her that she get to go to the circus as her birthday present. But he won't be sending her to the circus; Max and PJ will.
At an abandoned circus, Pistol was talking eagerly about the circus. Even though it's closed, Pistol refused to leave. When PJ then Max knocked the ticket booth, the Ringmaster angrily told them that the circus is eternally closed. Pistol confronted Ringmaster, so he threatened to call Giblet the Clown to get rid of them if they don't leave shortly. Giblet showed up and got rid of the boys, but not Pistol, since she's walked away. With Pistol left behind, the boys must repossess her before it will be too late.
In the circus tent, Pistol saw a Monkey in a locked carriage asking to be freed, so she freed not only him, but a lion (Pistol called him "Kitty"), an elephant (Annie), a bear (Boris) and a seal (Pistol called him "Puppy-thing"). Pistol told them to play Circus with her. Meanwhile, Max and PJ were searching for Pistol while Ringmaster unsuccessfully sold the circus because the client only wanted the animals.
Max and PJ found Pistol in the circus tent, where she started her role as a ringmaster introducing Annie, a peanut shooter, and Boris, a roller-skating balancing bear. Max and PJ advised Pistol to get out of the circus, otherwise Ringmaster and Giblet will spoil the fun, and as fate had it, they showed up. Ringmaster and Pistol had a conflict between caging and freeing the animals, and then Ringmaster called Giblet to capture the animals. However, he failed and was flattened, as Boris fell on him from a previous act.
Pistol called the Ringmaster not to cage the animals again, and he underestimated her, only to be met with a swift kick on the shin. After that, he recovered Giblet from his flat state and told him to trap the animals. Pistol threatened Ringmaster to leave the animals alone, but he just hung her on a beam. Even then, she still attacked him. Monkey goaded Ringmaster, prompting him to take a net to catch Monkey.
While that happened, Pistol released herself from being hung. Also, Monkey got help from "Kitty" in a way that caused Ringmaster to be scared. Max and PJ had to fetch Pistol, while Annie wanted to walk off, but was tied to a pole, thanks to Giblet. Pistol called the animals to hurry, and mentioned peanuts (Annie's favourite food), which strengthen Annie to break the pole and collapse the circus tent. Despite the escape, the animals were trapped in a cage again.
Max and PJ promised to compensate for the tent, but Ringmaster didn't want those, instead he wanted them out as soon as possible. He also told them his plan of selling the circus animals as dog food. Hearing this, Pistol sneaked away and freed the animals without the knowledge of Ringmaster and Giblet. Of course, the Ringmaster was glad that Pistol was gone.
At night in Pete's house, where Pistol kept the animals custody, Pistol fed the animals with food from the fridge. Chainsaw witnessed the animals, and was terrified. In order to avert attention, "Kitty" placed Chainsaw in a kitchen drawer while Pistol and the animals head for her room with a cake.
Pete heard noises in the kitchen and saw the mess that was left behind, and thinking Chainsaw was the culprit, he booted her out of the house. Pete then better makes sure the kids are asleep (so he could eat some food in private). He said his good-nights to son, and as he was walking across the passage, he stepped on peanuts leading to Pistol's room.
Pistol told the circus animals about a story with a happy ending about them and the Ringmaster. However, the animals had to conceal when Pete was about to enter her room. Everyone except Monkey went out of the window. Fortunately, Pistol managed to keep the secret of the circus animals from him. In the meantime, Ringmaster and Giblet were in search of the animals.
In the morning, Pistol attempted to ask her dad permission to keep the circus animals. Initially, Pete wasn't aware of it, but when he found out, he explained to her that he couldn't keep them. In addition, Ringmaster and Giblet showed up in time to retrieve the animals.
After the animals were taken away, Pistol was sad that the animals were going off, but an accident by Giblet caused the truck the animals were held in to roll downhill, along with Pistol, who actually climbed up the back to bid farewell to them. The truck was speeding away the traffic. Luckily, Goofy came by with his jeep, so Pete, Ringmaster, Giblet, Max and PJ took a lift, told Goofy to follow the truck, and together they chased it.
In the wild chase, Goofy drove past a bumpy ride that includes a roundabout, a steep hill to chase the truck. But then, the truck headed past the barrier of a bridge into the river. When they stopped, the gang thought that Pistol was gone, but the animals were on the other barrier of the bridge clinging onto the bridge. Pistol was sitting on "Puppy-thing" while the animals carried her up to safety. The Ringmaster was relieved that his to-be-dog-food animals were safe, but Pete refused the animal cruelty and bought the animals from him. Also, after that, Pete kicked Ringmaster and Giblet into the river.
When Max asked Pete what he'll do with the animals, he gave it some thought. Later, the animals were invited to play along in Pistol's birthday party. PJ and Max were glad that Pete was a genius with using the animals. But then, Max hinted to Pete about Pistol's interest in fishes, stating her desire to go to Seymour Seaquarium (and aquarium) next year. Pete had a sad face in the end.