Underdog breaks out of the phone booth, and hears the cries for help again. Underdog flies to the lady, who tells him that her little boy has been accidentally locked in a bank vault. With only this information, Underdog flies off toward the bank. He reaches a bank, crashes in, much to the shock of the occupants, and then proceeds to rip open the giant door to the vault. The bank president blows up at Underdog, saying that he's got the wrong bank! So, Underdog flies to the correct bank, and attempts to rescue the boy. But at first, nothing he tries works. He crashes through the vault door, only to crash through the whole building and the one next door as well. He tries using his X-ray vision to locate the boy, but instead, starts a fire! All the people in the bank are in a panic now! Underdog uses his atomic breath to blow out the fire, and in the process, blows virtually the whole building away! But at least the mother's little boy is found all safe and sound.

An army of giant robots take over the city and capture Polly. Underdog foils the monsters by using his high-pitched voice to destroy the robots' electronic brains. The robots aren't the only thing destroyed, but so is all of the city's glassware.

Simon, a mad scientist, creates a camera. This is not some ordinary camera however. When he takes someone's picture, the freezes them in the photograph!

Simon has frozen poor Underdog solid. All efforts to defrost Underdog fail. Somehow, Underdog defrosts himself and immediately flies around Simon and Cad so fast the two villains get dizzy. They fall down unconscious and are turned over to the law. Underdog then rescues the frozen people by using his super-hot atomic breath, defrosting them all in seconds. The episode ends with a group of people on the street saying "It's a plane," "It's a bird," "It's a frog!" & a man saying "A frog?" with Underdog saying: "Not plane, nor bird or even frog, it's just little old me, Underdog." before crashing into a building.

Underdog is having an average day. He foils a bank robbery, rescued Sweet Polly and made himself useful across the world. Meanwhile, a million, million miles away on the planet Zot, King Klobber is upset. It seams that his daughter the princess wants to get married and can't find anyone suitable.

The story of Zot continues with King Klobber searching the galaxy and then the universe for the strongest warrior. They discover Underdog on an insignificant planet named Earth. King Klobber sends a fleet of spaceships to capture underdog and return him to the planet Zot.

Riff-Raff's plan goes into action: they kidnap Sweet Polly Purebred, tie her up and put her in a balloon, and set up a bunch of other balloons with record players inside them playing records of Sweet Polly shouting "HELP! HELP!" Once the plan is under way, Riff-Raff's gang heads over to the train station and hold up the stationmaster, and Underdog leaves his post and heads over to the balloons, only to be confused by the record players.

After overcoming a mutiny at sea Polly and the gang continue on to the south sea Island to find "Fearo the Ferocious". Upon arriving at the Island Underdog saves the day as he overcomes ferocious dinosaurs.

Underdog is shrunk by Simon's new evil device and is placed alongside Polly in a birdcage. Luckily, our hero's powers are still useful and they break out of the cage. Seeing that his shrinking of people with his trick flower is taking up too much time, Simon decides to put his shrinking water into a rainmaking machine. Simon and Cad return to the lab only to be tripped up by a trap set by Underdog and Polly. Simon reverses the trap, and catches the pair inside of a rat hole. An army of rats soon corners Polly and Underdog.

The Emperor and Empress of Maldamere have a scientist who has created a tidal wave making machine, and plan to use it to destroy the surface world. Concerned about the giant waves that are threatening the world, Sweet Polly Purebred and Professor Moby Ahab- a noted oceanographer- head for the South Seas to investigate. But their trip to the South Seas are being watched by the evil monarchs of Maldamere. The Empress orders the release of her army of giant whales to stop Polly and the Professor. Seeing the attack, Polly calls for Underdog who foils the whale attack. Angered, but not willing to admit defeat, the Empress orders her guards to capture Polly and the Professor in their submarine. The very moment that their bathysphere reaches the ocean's bottom, Polly sees a strange and horrifying sight.

Things looked bad for Polly, who's speeding down a car downward on a slope, and a wheel on the car even comes off. Fortunately, Underdog flies down and saves her just as the car falls off the cliff. After dealing with Polly, Underdog announces on the TV news that Riff Raff has the diamond. Enraged, Riff Raff thinks of a way to make sure Underdog doesn't bother him again. Later, Underdog finds signs that lead to Riff Raff's hideout, but in reality, he is lured inside a cave that starts eroding inside when Mooch blows it up. Meanwhile, Riff Raff is looking for an Underdog impersonator. He finds one named Tap Tap who is entirely perfect. Tap Tap and Riff Raff rob the bank, much to everyone's surprise when they see "Underdog" doing a crime.

After Polly's plane crashes, Polly asks Underdog to pick some flowers while she waits under a tree she thinks is friendly. But the 'friendly' tree turns out to be the witch of Pickyoon. As Polly tries to scream the witch gags her and takes her to her castle. Underdog is at a loss to where Polly is.

Simon is trying out his latest evil invention, the weather making machine. This dangerous device creates artificial storms and other natural disasters which Simon hopes to use for his own plans of world conquest. But it is not without faults; the weather machine's powers are uncontrollable near itself, that is, Simon's Lab. Cad comes up with an idea: why not use the machine from another spot not on the Earth. Intrigued by this idea and the fact that Sweet Polly Purebred and two astronauts are heading for a moon expedition, Simon and Cad head for Cape Carnival and take over the spaceship and capture Polly. The trio head for the moon with Simon's diabolical weather machine.

Underdog is requested to deliver gold bricks from the bank to an undisclosed location. But Riff Raff and his henchman Mooch disguise themselves as toll guards and surreptitiously steal the gold. When Underdog gets to the secret location, the gold bricks are gone and Underdog is placed under arrest for grand larceny.

It is the day of the National Olympics, and Sweet Polly Purebred is there reporting the news to the people there and the TV watchers. The first event is the broad jumping contest. One of the contestants jumps, but keeps soaring high and high into the air. Everyone is amazed, but the same thing happens with weightlifter and the pole vault jumper. As a result of these strange incidents, the Olympics are cancelled and scientists get to work getting to the bottom of the incidents. Professor Bruno Heimerdown comes to the conclusion that the phenomenon might have to do with the new planet they recently discovered. General Ricketts has a meeting at the White House that they have to go to the planet and see what's on it, as it might wipe out Earth, and only Underdog is the strongest person to do so.

Cad, Simon Bar Sinister's henchman, replaces real phone booths with Phoney Booths. When he returns to the lab to tell his boss all the booths have been replaced, he asks what they do. Simon demonstrates by deceiving the milkman that his office wants him to call and directs the unsuspecting milkman into one of the Phoney Booths. The booth jumps and spins and when it opens, the milkman emerges in a trance repeating 'I will do what Simon says'. Simon instructs the milkman to destroy all his milk bottles, then remotely tells him to drive his milk truck into a pole. Then he tells him to go home and await further orders.

Sweet Polly Purebred calls on Underdog to remind him that it's his birthday, and that she plans to give him a party. Meanwhile, the curator in London wishes to loan the famous Excalibur Sword Collection to the San Francisco Museum. Fearing that someone will steal try to steal it, they send a message to Underdog for his assistance to guard the collection. While en route via train, Riff Raff and his gang attempt to steal the sword collection by derailing the train. When the train wrecks, Underdog engages Riff in a duel with the sword collection that was scattered from the wreck. Riff and the gang flee and Underdog attempts to put the train back on the track but seems to be in pain from his back. An ambulance is rushed to the site.

When crops from all over begin to disappear, Sweet Polly decides to visit the location of the disappearances. She falls into a hole and lands underground. There she is met with King Mange, who explains that he and his men have been stealing the crops to weaken the surface dwellers so that they can conquer the Earth. Polly tells them that Underdog will stop them, to which King Mange replies that their weapon, the Molehole gun will burrow a hole into anyone, including Underdog.

King Cup - the evil, spoiled monarch of The Flying Sorcerers' planet - can't get cake that tastes good. So he send his sons Bric and Brac to find a new baking slave. Their efforts are not too successful, since they get slaves from the planets of Zot and of the Magnet Men. Then King Cup sees Polly hosting a TV cooking show on Earth and he knows he has found his new baking slave. The Evil despot sends Bric and Brac to Earth to capture Polly.

Simon becomes increasingly frustrated with Underdog always stopping him in his endeavors. Cad suggests that the only way to stop him is if he forgot who he was. So Simon embarks on a quest to create an amnesia weapon. His first attempt which has the victim seated in a chair and have a hammer land on their head works, but Cad reads that the machine's not effective on people with hard heads. So Simon tests it on Cad, and finds the latter was right. Finally, Simon reads about creating a Forget-Me-Net, which, when placed over someone, makes them forget who they are. After successfully trying it on a victim, he then sets out to try it on Underdog.

At the Mid-town Modern Art Muesum, a special showing was being held for the painting "Whistler's Father." As Riff Raff sets out to steal the famous painting, Whistler's Father. To do so, he calls upon the services of many gang hooligans. Each have a specialty. Riff Raff informs the gang that they will be using guerilla warfare tactics to try to rob the painting from the museum.

One night, in a new scheme, Simon takes Cad to a street corner where he shows him a tricky traffic light control box. On the box are two buttons; one will sound an air raid siren that will send everyone in the city into their homes or air raid shelters. When Simon pushes the second button, it will slam all the doors and windows shut and trap everyone inside thus making the plunder of the city easy. The two fiends leave the scene to prepare for the take over of the city.

Armies of ghostlike creatures are stealing all of the Earth's silver. Earth's military forces and the police are powerless to stop these crooks because the creatures disable the authorities' weapons with lightning bolts. One night, one of the silver thieves steals Underdog's silver ring. When he is wakened by the theft, he is shocked by his assailant and left frozen solid.

Riff Raff and his mob have tried 9 different crimes in the last month but Underdog stopped them all. So Riff decides to move out West. He leaves the city and takes over a little western town, renaming it "Riffraffville."

The planet Felina's milk wells have run dry which makes the evil ruler Overcat mad. He and his men go to Earth and steal all the cows. However, they don't know how to get the milk from them so they grab someone who does... Sweet Polly!

Sinister and Cad invent another evil device they call the Big Dipper, a machine that can dry up all of the world's water supplies. On its first trials, the Big Dipper does little more than flooding Simon's lab. After a few false starts, the Big Dipper is finally ready to destroy the world's water supply and Simon may finally have a means of taking over the world!

The prison warden's chief officer informs him that Riff Raff is assembling a gang and is planning on escaping. They feel that they need to tell Underdog, so they send for Sweet Polly to call for him. When Polly arrives, the chief officer explains what was overheard in the prison from some of the prisoners that Riff has obtained as part of his gang. Polly then calls for Underdog, who, disguised as shoeshine boy, is stalled waiting for a woman to exit the phone booth he needs to change in. Upon hearing that Underdog has been called, Riff makes the decision that his newly formed gang needs to leave immediately, taking with them a disguised little fella. When the gang asks why he needs to be taken along, Riff responds, 'Just in Case.'

A strange object crash-lands on earth. A group of scientists check out the mysterious object, determining that it's a harmless, dead comet. The scientists leave the scene unaware of the fact that a secret door opens from the center of this strange thing and two evil looking space aliens emerge from this strange object.

Simon invents the Valentine Vault which turns people into paper valentines. He orders Cad and his two henchmen to kidnap Sweet Polly... to set a trap to catch Underdog in the machine.

Sweet Polly is reporting a launch in space but the capsule is pulled off course to an uncharted planet. On this planet, the evil Zorb used a magnet to pull the capsule to his planet. Zorb explains to his henchman, Cron, his plan to use the capsule as a decoy to lure Underdog. The capsule lands on the planet and gets stuck in the mud. A call is made to Underdog to rescue the planet. After freeing the ship, Cron approaches with a charm and puts it around Underdog as a gift. Underdog, thinking he is a friend suggests to bring Cron back to Earth.

After a violent thunderstorm ravages the city, the community gathers in front of one of the steel buildings to see a message revealed inscribed on its side: 'To Underdog, A Rhyme in Time Saves Nine'. Sweet Polly asks Flim Flannigan at the police station what it means. Flim explains it could only be the work of Slippery Eel. A few weeks earlier, Eel, Fish, and their henchmen attempted to rob an armored car. They were caught by Underdog and were sent to the maximum prison with the electric fence. Still determined to get out, Slippery Eel tells his boys that he is going to climb the fence now that the power didn't seem to be on. Midway climbing the fence, the guards see him trying to escape and turn on the electricity. However, instead of electrocuting him, it electrifies him, and he then claims that he is now 'The Electric Eel'. He shoots bursts of electricity at the fence and wall and escapes with Fish and the gang, all the while vowing to get even with Underdog.

A series of crimes are being perpetrated all over the country. Underdog tries to solve them, but finds no clues as to who is behind the crime wave. Who is the new super villain behind the crimes that are paralyzing the country?

Simon Bar Sinister makes a vacuum gun which he uses to catch Riff Raff, Electric Eel, Batty man and all of their men for his army while Underdog is saving a sinking ship.

Cad, Simon Bar Sinister's henchman, replaces real phone booths with Phoney Booths. When he returns to the lab to tell his boss all the booths have been replaced, he asks what they do. Simon demonstrates by deceiving the milkman that his office wants him to call and directs the unsuspecting milkman into one of the Phoney Booths. The booth jumps and spins and when it opens, the milkman emerges in a trance repeating 'I will do what Simon says'. Simon instructs the milkman to destroy all his milk bottles, then remotely tells him to drive his milk truck into a pole. Then he tells him to go home and await further orders.