While venturing in a snowy world, Toad is kidnapped by a near-sighted Birdo who is convinced that he is her missing baby. The Marios and Princess set out to find him before the Birdo drives him crazy. And if that wasn't enough, Koopa learns of their whereabouts, and sends his troops after them.
While trying to rescue the Princess from an abandoned mine, the Mario brothers find themselves running from Sheriff Mouser and his minions who are after the large reward Koopa has promised for their capture.
Mario and Co arrive in Cramalot, only to be assaulted by Beezos. They are saved by Mervin the magician, who tells them about how Koopa took over Cramalot, and how he can be defeated with a golden plunger that one must pull from a golden sink. Although Mario succeeds in pulling the plunger, he ends up losing it to Koopa, and the group is sentenced to execution in a dungeon.
Mario and Co are traveling through a desert, dying of thirst. Thanks to a booby-trap, they wind up in the palace of Sultan Pasbah, who tries to force Princess into his harem, while the guys are sent to the dungeon. Through total fate, the Marios discover a magic lamp. However, it contains a grouchy genie who apparently offers no help in getting Princess back from the sultan, or from Koopa, who just showed up to purchase her.
The Marios and Toad are trying to save the Princess from Koopa's riverboat. When their plan goes horribly wrong, Toad gets caught and the Marios barely escape with their lives. The Marios then meet up with Mark Twang, a man who's in a race with Koopa. The Marios and Mark now have to work together to beat Koopa and rescue Princess Toadstool and Toad.
Mario and Co head to the Linguini Empire to attend a benefit spaghetti dinner. When they arrive, Princess and Toad are seperated from the Marios and meet Koopa, who's taken over. The Marios eventually get caught and are forced to fight Triclyde in the colosseum.
Desperate for cash, the Marios trade the royal cow for bean seeds. Princess scolds them, and accidentally sneezes, blowing the beans into the yard. Overnight, they grow into a beanstalk. The next morning, Mario and Co climb the beanstalk, which takes them to a gigantic castle in the sky, which is occupied by Koopa, who's now giant-sized.
Mario and Co arrive in Rotunda Land, which is ruled by the uptight Queen Rotunda. After being caught, Mario unintenionally gets Rotunda to drink a love potion, causing her to fall in love with him, much to his dismay.
To help Toad pay off his debt to Fry Guy, Mario and Luigi enter a bike race in hopes to collect the prize money. But what they don't know is that it's all a trap planned by Koopa.
The Princess falls into the Fountain of Youth, transforming her into a baby. Now, the Mario Bros. have to protect her while looking for a way to reverse it.
Mario and Co head to the planet Quirk to save the natives from Koopa, who's enslaved them all. As luck would have it, Koopa ends up capturing Mario and Co as well.
Mario and Co have hired on as deckhands aboard Captain Clump's ship. As luck would have it, Koopa captures the Princess so that he can auction her off. He then has her friends tied to the mast of Clump's ship, which is left to sink into the Trouter infested waters.
Mario and Co arrive in Robo Land, only to be attacked by Koopa, who's donned a robo suit. They meet up with Bunsen, a robot Mushroom, who temporarily gets rid of Koopa. Bunsen then takes the group to Dr. Nerdnick, the man who was tricked into building the robo suit, and is being held captive by Koopa's guards. Everything goes well, until Koopa returns and captures Princess and Toad.
Mario and Co have entered Turtlevania, and seek refuge in Koopa's castle. There, they learn of Koopa's evil plot to capture Princess Toadstool and turn her into a vampire. Another problem they must face is that the estate is swarming with monsters.
Mario and Co are traveling through the Amazon Jungle, in search of Sheldon the witch doctor, whom they hope can help them banish Koopa. The Marios and Toad are assaulted by Albatoss with itching powder, and Koopa kidnaps Sheldon. It's up to Princess to rescue Sheldon from Koopa.
The Marios travel to Aqua Land, where King Koopa (Under the alias of Barra-Koopa) has enslaved the Mermushrooms, forcing them to steal treasure from all the sunken ships. Can the Super Mario Bros. win this battle of the bottom?
Mario and Co meet Hercufleas, a legendary hero and a friend of Toad's who recently became incredibly fat and lazy. Hercufleas' job is guarding The Great Balls of Fire, which are soon stolen by some Beezos. When the Marios fail to get them back, they turn to Hercufleas. But first, they have to get the big guy back into shape.
Mario and Co arrive in the Oriental city of Sayonara, looking for Super Sushi, an experimental food that can double one's size and strength. They also find Koopa, who's now gigantic, and destroying the city. Mario and Co meet up with the creator of Super Sushi, who explains that Koopa ingested too much, and needs to be stopped.
Koopa kidnaps Romano's love, Joliet, so the heroes set off with him to rescue her and reunite them so they can marry, provided that their fathers quit fueding.
Mario, Luigi, and Toad have to rescue Princess, who was thrown into a volcano by the unknowing people of Waki-Waki, from Koopa, who's disguised himself as a fire god.
It seems to good to be true for Mario and Luigi when they find a way back to Brooklyn. But when Koopa attacks, the brothers must decide between their old home and new friends.
Mario and Co arrive in Victoria, hoping to find the great dectective, Herlock Solmes. When they find out that Solmes is missing, Mario dons the name Sherlock Mario, and sets out to find him. Turns out Solmes was kidnapped by Koopa and his gang. Koopa then goes after the Retro Reuter, a weapon that clogs drains, to flood the city with sewer water.
Mario and Co team up with Hooded Robin to get back the coins Koopa stole from the citizens of Sharewood Village. However, Robin gets caught by Koopa, so Mario and Co have to save him along the way.
Koopa has stolen all the spaghetti sauce in Car Land, where everyone drives around in some sort of vehicle. Mario and Co have to find a way to stop Koopa, if they can.
Koopa uses a magic flute to kidnap Pasta Land's children, so Mario and Co head to his castle to get them back. They soon find themselves trapped in the dungeon, and they need to think up a plan to get the children home.
Koopa has kidnapped King James of Rap Land and is making all the citizens turn over their money to him. Mario and Co need to rescue James, cut Koopa's power, and kick Koopa out of Rap Land.
Koopa and Lakitu use a weather satellite to cover Pasta Land in snow. Mario and Luigi go after him in a flying carpet, but Koopa easily destroys it. They then go after Koopa in a special airplane that has flying carpets for wings.
Koopa steals a pot of gold coins belonging to a leprechaun named Murphy. Without his pot of gold coins, Murphy is a jinx who's luck is so bad, that Shamrock Land will flood if he doesn't get his coins back. Mario and Co agree to retrieve the coins, and almost succeed, but Murphy's bad luck results in them being caught.
Koopa has turned all the mushroom people into rocks and has captured Mario & Luigi. He is about to kill them, but spares them in exchange for Princess' hand in marriage. She agrees, but only if he releases the mushroom people as well. Shortly after, Koopa turns back on his word and reverts the mushroom people back into rocks. Now the Mario Bros. have to find a way to stop the wedding.
The Mario Brothers arrive in El Desert Land to meet the legendary masked hero Zero. However El Koopitan has captured Zero so the Mario Brothers disguise themselves as Zero and Zero Plus One in order to save the real Zero.
When a sea monster attacks the town of Happy Harbor, Koopa offers to stop the monster if the citizens make him their king. Mario and Co work with the fearless Captain Abidab to get rid of the monster themselves, but Mario, Luigi and Princess get swallowed by the monster, which is actually a submarine of Koopa's.
Mario and Co have to defend themselves and General Washingtoad's army against the Koopas. When Koopa threatens to attack, Luigi travels on horseback to warn everyone ala Paul Revere, shouting ""The Koopas are Coming! The Koopas are Coming!"", but he gets caught in the process.
In Caveman Land, Mario is bitten by a snake and ends up petrified. The only way to revive him is by feeding him pizza. But, since there is no readily available pizza in Caveman Land, the others have to work together to try and make him one.
Mario and Co are in the Oriental City of Sayonara, where they hope to find a martial arts master by the name of Misaki. Koopa finds them first and kidnaps Princess and Toad. Misaki rescues the Marios and teaches them Plumb-fu, so that they can fight Karate Koopa.
Mario and Co have entered Sock Hop Land, where superstar Elvin Parsley has been frozen by Koopa, who's hanging out at a malt shop. When they go to rescue Elvin, Koopa kidnaps Princess yet again.
Koopa Klaus has taken over Santa's workshop at the North Pole and has frozen all the elves and toys. It's up to the Marios, Toad, and Princess Toadstool to stop him.
Koopa has turned the citizens of Pyramid Land into bricks for his new Koopinx. Mario and Co come to their rescue, only to be caught and get trapped in a pyramid. They need to find a way to save the Mushroom people, but first, they need to save themselves.
Koopa kidnaps Luigi, Princess and Toad, along with a trunk of gold coins they were transporting across Sudden Death Valley, leaving Mario to die in the heat. A native Mushroom named Pronto comes to Mario's rescue, and Mario takes on the role of the Provolone Ranger in order to rescue his friends.
Mario and Co are in the Wild Wild West, where Koopa unintentionally chases them into a lost gold coin mine. When Koopa hears of the mine, he enslaves the local townsfolk into mining all the gold coins for him.
While travelling through Jungle Land, Mario is seperated from his friends thanks to Koopa and an Albatoss. Mario then suffers from amnesia, and is taken in by an ape couple, who change his name to Marzan and teach him the ways of the jungle. Meanwhile, Luigi, Princess and Toad have to find Mario and knock some sense into him.
Mario and Co find themselves in Down Under Land, where Koopa steals the local town's magical statue which can scare off crocodiles. With the statue gone, crocodiles invade the town and try to eat everyone in it. It's up to Mario and Luigi to get the statue back from Koopa before it's too late.
Plumbers Academy Mario loses his golden plunger after a battle with Koopa. He tells Princess & Toad that this was a special plunger because it was given to him by the President of the United States. In pre-show flashback mode, Mario tells how he and Luigi became plumbers, and how they had to put up with their overly strict boss, Sgt. Kooperman (who sounds a lot like Koopa). Kooperman ended up flunking the Marios, who soon found themselves facing their biggest plumbing challenge ever.
Waldo the wizard befriends Mario and Co and intends on using a shrinking potion to shrink Koopa. Unfortunately, Toad spills the potion on the Marios, which undoubtedly shrinks them. Now the Marios have to elude the Koopas, while Waldo tries to conjure up an antidote.
The Mushroom Kingdom is celebrating the recent defeat of Koopa. On top of that, a warp pipe to Brooklyn has opened up. At long last, the Marios finally make it back to Brookyln, only it's not the Brooklyn they remember.
Mario and Co team up with the faceless explorer Indiana Joe, and go after the Lost Mushroom, a statue that grants wishes. But Koopa claims he's the heir to the Lost Mushroom, and goes after the Marios with his gang.
Mario and Co are on their way to protect a Mushroom space colony, only to be caught by Darth Koopa's ship, the Koop Star. They fight off some Stormtroopas, followed by Koopa himself, but Koopa ends up freezing them. After having them thawed out, he gives Princess two options: Tell the colonists to surrender, or have their planet destroyed with his Birdo Ray. When Princess refuses to give up, the Birdo Ray is set to fire in thirty minutes, and Mario and Co get dropped into the Koop Star's trash compactor.
Koopa sentences Mario and Co to the island prison of Koopatraz. There, they meet up with Toad's long long grandfather, who happens to be their cellmate. Together, they try to work out a way to escape from the prison.
It's wintertime, and Mario and Co are on their way through the woods to visit Princess' sick grandmother. Before they entered the woods, Koopa stole everyone's lumber, casing them to all freeze. While Mario, Luigi and Toad stay behind to defrost the villagers, Princess continues to her gramdmother's house alone, where she is pursued not only by Koopa, but by the big bad wolf as well.
Koopa plans to use Mario and Luigi's brains for his monstrous creation. When the Marios set out to stop him, an accident in Koopa's lab turns Koopa himself into a mindless monster.
When Koopa turns Secret Agent James Blonde to stone, the Marios are selected as his temporary replacements. Their first assignent is to stop Koopa from robbing Fort Hard Knocks, but they end up getting captured, and taken to Koopa's hideout.
Koopa and his gang are robbing banks in Crime Land, and have acquired special hats that repel all projectiles. Mario and Co are unable to beat them, so they need to sneak into Koopa's nightclub and steal the hats.
Koopa's kidnapped Princess, and Mario, Luigi, and Toad try to rescue her, failing numerous times. Mario realizes that Koopa's ego is his weakspot, so they use a Trojan Koopa (instead of a horse) to break into his fortress. However, it all doesn't go as planned, and they find themselves surrounded by Koopa's guards.
A "slime ghost" is in Mario Bros Plumbing, so Mario contacts Ernie Hudson from Slime Busters. Episode based on Ghostbusters. The ghost takes control of Luigi's body, forcing Ernie to battle him.
Basketball star Magic Johnson guest stars and shows Mario and Luigi some magic tricks.
Mario and Luigi are visited by their neice, Marilyn. The two are surprised at how big she's gotten, but Marilyn's uninvited friends and the party she hosts prove to be an even bigger surprise.
A cooking mishap turns Luigi into a zombie. Elvira guest stars as herself.
Mario must help Elvira deal with a mummy.
When Little Robert (Willard Pugh) comes over, the Mario Bros. attempt to get him to sing on tape.
Mad Donna's car breaks down and asks the Mario Brothers to use their phone. However, Mario places a magic love apple on the table and when Mad Donna eats it she falls in love with Mario.
After a dream about their grandmother Mario calls in a psychic (Elaine Kogan) to try to communicate with the deceased Grandma Mario.
Mario finds a treasure map in their apartment, so the brothers ask Inspector Gadget (Maurice LaMarche) for help searching for the treasure.
When a pizza delivery lady says that she adores a man who can "eat his weight in pizza" Mario attempts to do just that. Eve Plumb guest-stars.
When Little Robert comes over, the Mario Bros. attempt to get him to sing on tape. (The live-action segment in this episode is a repeat of "Tutti Frutti, Oh Mario.")
While fixing their furnace, the Mario Bros. are visited by an old man named Fred Van Winkle. Apparently Fred has been asleep for the last 60 years. Mario and Luigi decide to introduce him to the wonders of modern life.
