In the wilderness, Batman and Plastic Man investigate a hidden base and find shattered cages and enormous footprints leading toward a Camp Scout jamboree. They follow the abducted scouts, who have been abducted by the escaped Sasquatch beasts, sound asleep. The two heroes try to keep as quiet as possible while freeing the scouts. However, eventually Plastic Man disturbs a squirrel, which bites his hand. He manages to tie his lips together and keeps from yelling out. When a fly threatens to awaken one of the Sasquatches, Plastic Man catches it. All goes according to plan… until one of the Scouts sneezes and Plastic Man says Gesundheit. The heroes knock out the beasts and emerge triumphant.
Later, Plastic Man swears Woozy Winks in as a duly deputized sidekick. They go the Plaz Cave, Plastic Man's garage, and shows off his plastic crime-fighting equipment. It's all modeled on Batman's equipment, and Plastic Man admits that he'd like to learn some self-control from Batman. They rehearse their secret signal but are interrupted when Ramona, Plastic Man's girlfriend, arrives and tells him to take out Baby and Schnitzel the dog and expose them to some culture. Plastic Man tries to object but soon gives in.
As Plastic Man and his sidekick go to a museum, a huge rubbery figure stalks the streets and enters the museum. Schnitzel pulls Woozy into the villain, who shoves the security guards aside. Woozy goes to get Plastic Man, who recognizes the villain as Rubberneck. Plastic Man goes after him and leaves Baby with Woozy, who quickly loses the child. Meanwhile, Plastic Man sneaks up on the villain disguised as a painting and tries to ensnare him. However, Rubberneck tosses him through the window where Batman grabs him before he goes flying off across the city.
While Woozy tries to track down Baby and Schnitzel, the heroes move in on Rubberneck. He knocks Plastic Man outside and goes after them, where Woozy has gotten Baby and Schnitzel outside. Batman manages to save them and Plastic Man fills himself with water and bounces Rubberneck away while blowing himself apart. As Plastic Man reassembles himself, he's unaware that Kite Man, hiding in the shadows, has captured a piece of him.
Afterward, Plastic Man and Woozy bring Baby home and avoid telling her what happened. Unfortunately, all the TV newscasts show the robbery at the museum. Ramona is less than happy, but is interrupted when Batman arrives. Batman confirms that 2.2 grams of Plastic Man are missing and explains that the robbery was a ruse to get to Plastic Man. Plastic Man can't think of anyone who dislikes him, but Batman is confident that Kite Man, Plastic Man's former boss, is responsible. Batman tells Plastic Man to stay with his family.
At his lab, Kite Man has created a theta ray gun that will destroy Plastic Man. It tests successfully, altering the sample's elastic properties and rendering it solid, and he tells Rubberneck to steal the industrial-strength energy module that he needs to power the ray.
Batman takes to the streets after Rubberneck but discovers that Plastic Man has substituted himself for the Batmobile, and Woozy has stowed away. They give chase to Rubberneck and a high speed chase ensues. Rubberneck's truck goes off the road but he bounces away. An angry Batman warns that because Plastic Man disobeyed his orders, his family is in danger.
Ramona answers the door to discover Kite Man on her doorstep. He escapes with a kite, towing Ramona, Baby, and Schnitzel behind him, and boasts to Plastic Man that he'll soon pay. Plastic Man realizes that it's his fault due to his lack of self-control, but Batman tells him to pull himself together. His confidence restored, Plastic Man transforms into a car and Batman directs him to the Franklin Museum, a museum dedicated to the most famous kite-flyer of all. Kite Man is there, and explains that as a boy he cut corners and flew a kite in a lightning storm to emulate his hero. The resulting electrical shock gave him a psychological trauma and forced him into a life of crime.
As Ramona, Baby, and Schnitzel hang suspended from a kite above, Kite Man reveals his anti-plastic gun and unleashes a kite to tie up Batman. He then tells Plastic Man to step out and let himself be shot. Plastic Man insists on making things right and steps forward. Kite Man fires the beam and Plastic Man is petrified. Batman tells Kite Man to release the hostages now that he has his revenge, and Rubberneck unfastens the kite. Batman frees himself and tries to snag the departing kite, but is forced to hold off Rubberneck.
When Kite Man tries to fire his gun at Batman, Woozy tries to help and inadvertently stumbles repeatedly, knocking Batman out of the way and Kite Man away from the controls. Woozy takes over and changes the settings, causing the gun to rubberize items. A stray beam hits Plastic Man, restoring him to normal, while Woozy tries to stop the gun. A beam hits Kite Man, turning himself into a rubbery puddle, and Plastic Man knocks him away. Kite Man soon masters his new elastic self and soars back into battle, and Woozy tries to pull the cooling hose on the gun. It doesn't go well, and Batman is hit as well. He puts his new elastic abilities to use and defeats Rubberneck.
As Kite Man smashes Plastic Man, Plastic Man stretches past him and tries to free his family. Kite Man stops him but Plastic Man deals the final blow, knocking him out. The last ray from the cannon hits Kite Man and Rubberneck together, solidifying them into a rubber statue. Batman takes out the gun with a Batarang and Plastic Man launches himself into the sky, cuts his family free, and lowers them to safety as a parachute.