Mario and the gang play some retarded Mario Kart game modes to see who is the best driver.
The First Race of the Episode
The episode starts with Po but she is on a race track and gets run over by Wario, who was racing with Toad. Dodging a Bob-omb thrown by Wario, Toad throws his "Crazy Girlfriend" (Toadette) at Wario causing him to crash. Toad then continues up a boost ramp only to crash into an invisible wall and fall into a trap that Waluigi made.
The camera then zooms down and it shows Luigi crying and Toad stuck in Waluigi's trap as Waluigi looks on. Waluigi then gets in his kart but is stopped when Fishy Boopkins accidentally topples a tree that he repeatedly drove into onto him, crushing him. Fishy Boopkins exclaims that he was playing with that before being blasted away by a bullet bill from Bowser, who then drives off, doing a dance along the way. He then stops and backs up when he sees Peach who has crashed her kart (which is now on fire) beside a tree. Bowser then takes the opportunity to confess his love (with flowers) for Peach, only to scream in horror when Peach blows him up as well as herself with a Bob-omb she summoned while screaming, "YOLO."
The camera then zooms to SMG4, who is acting as the Lakitu. He is annoyed at the fact that they cannot have a normal race. He then asks, "And where the hell is the other racer?" which is referring to Mario. The camera then zooms to Mario, who is still at the start/finish line driving in a circular fashion (donuts) from the starting position while making an airplane noise (he was either doing it out of stupidity or because he anticipated the racers taking each other out). SMG4 then states how they have already done seven races, yet they still cannot determine a winner due to the racers trying to take each out other instead of racing. A different Toad then appears suggesting Mario Party figure out a winner, but SMG4 kicks him. SMG4 then states that since the racers would prefer to hurt each other, they would instead do a battle royale.
The camera zooms to view the battle arena, then to Mario, who is ready, and Luigi, who is crying nervously. SMG4 then goes over the rules: "Don't let your balloons pop, and the last one holding a balloon wins." SMG4 then signals for the battle to begin and an air horn sounds. All of the racers attempt to crash into each other before spinning out in different directions. Mario then hits an item box and receives the 3 green shells. He is amused and proceeds to toss them like crazy in every direction, hurling Fishy Boopkins out of the racetrack in the process. Toad then hits an item box and receives a golden mushroom, who then shouts, "YEAH SHROOMS!" and takes off flying crazy across the racetrack. Waluigi then hits an item box and receives a banana. Displeased, he cheats and shakes the item box and receives a coin. Still displeased, he shakes it again and receives a rocket launcher. He is delighted and proceeds to blow up Wario, who has set up bananas around him, to no avail. Luigi then comes along and gives Waluigi his famous death stare. Waluigi fires a rocket at Luigi only for Luigi to stand up and catch it in his hand. As Waluigi screams in terror, Luigi effortlessly throws it back, which blows up Waluigi.
Luigi is then hit and eliminated by Toad who is still using the golden mushroom. However, Toad himself goes too fast to the point where when he stops, only his skeleton remains. The camera switches to Peach who is joyfully driving around until she nearly falls off the block, where a Chain Chomp is about to pass by below. Mario then comes along and Peach asks for help. In a parody of a scene from The Lion King, Mario states "Long live the king," and pushes Peach and her kart off the block just as the Chain Chomp passes by, resulting in her getting crushed.
Mario then makes his way toward the middle of the arena where Bowser is waiting on the other side and the two charge at each other, having started a joust. Just as they are about to collide with each other, Fishy Boopkins appears, apparently having survived the ordeal with the green shells earlier (though his kart was destroyed in the process, and he only has one balloon left) and he hurls banana peels across the center of the arena.
Bowser and Mario both slip on the banana peels and fly into the air. For a moment, Fishy Boopkins thinks that he is the winner, much to his surprise. However, Bowser crashes down on top of him, and then Mario crashes down on top of Bowser, eliminating all three of them. The battle is a draw, and SMG4 gets angry and exclaims how he needs to give the trophy that he is holding to someone. He then decides that the current game modes are not decisive enough and that now he is going to use his own game modes.
The camera zooms to view another battle arena shaped like a doughnut. SMG4 then goes over the rules: Whoever defeats the boss wins. Luigi then asks who is the boss. Unfortunately, said boss turns out to be Link from The Legend of Zelda. Driving an overpowered vehicle, he effortlessly dispatches the racers, stabbing Toad in the head with the Master Sword (though thankfully, Toad is not harmed), and blowing up Wario (who tried disguising himself as a banana peel) with the dreaded Blue Shell. After Link attacks Peach, Bowser angered, attempts to strike him, only to be disoriented with Gust Bellows, causing him to fall into the lava. Waluigi tried hitting Link with a green shell, but after the Hero of Time glares at him, he eliminates himself by jumping into the lava, but not before saying "I'll see myself out". With only the Mario Bros. and Boopkins left, the situation looks really grim. Luigi suggests working together, and Mario ends up having an idea. He grabs both Luigi's and Boopkins' karts and attempts to ram into Link. However, the Hero of Time takes out and uses an Invincibility Star, resulting in the trio eliminated and the battle once again a draw. SMG4 angered that no one managed to beat Link, punches himself in frustration before admitting the unforgiving difficulty of the mode (while Link does donuts in celebration). He then decides on a much easier game mode, which according to himself, is so easy that even an idiot like Mario could do.
SMG4 explains the rules: Mr. Toadsworth needs a ride to his retirement home. Whoever delivers him to the retirement home wins. SMG4 then signals to begin and an air horn again sounds. All of the racers then crash into Toadsworth and try to take him. Toadsworth lands in a parking lot and is taken by Toad. As he is busy laughing, Bowser takes Toadsworth from him. However, Peach hires a hitman who takes out Bowser with a sniper, allowing her to take Toadsworth. The camera then switches to Toad, who sees Waluigi and Luigi driving by, Luigi's kart on top of Waluigi's kart.
Toad then goes to a garage and upgrades his kart to a monster truck. He then catches up with Peach and blows her kart up with a Bob-omb before taking Toadsworth. Waluigi soon catches up to Toad, but so does Wario, Luigi, and Fishy Boopkins. As the four of them drive side by side trying to catch up to Toad, Toad crashes into two people and Fishy Boopkins crashes into a police officer's table, ruining the cop's donut. Upset and triggered over his doughnut, he summons the police force, and soon a whole team of officers is chasing them.
The police open fire at Luigi, causing him to crash. He screams at Mario for help, but Mario is busy crashing his kart into random people while badly singing. Back at the chase, Toad is determined to deliver Toadsworth to the retirement home, but Waluigi catches up to him. He crashes his kart into Toad's windshield and the two fight for Toadsworth. The monster truck then hits barricades and rolls over against some trees, hurling Toadsworth from them as the police descend on Toad and Waluigi. Toadsworth lands in Wario's kart, but Wario is stopped by Fishy Boopkins' father, Joe.
Fishy Boopkins introduces Wario to his father before telling his father that Wario was very mean to him and asks him to do something. Wario tries to back up, but Fishy Boopkins' father hurls Wario's kart with one of his tentacles, sending Wario and Toadsworth flying, with Toadsworth flying into the entrance of the retirement home and crashing through the glass doors, where an Old Man exclaims, "What? Who's that?" whereas Wario is sent flying to the end of the street. SMG4 is shocked and states that it was close, but there is finally a winner.
After a short drum-roll, he states that SMG4 himself is the winner because everyone else apparently sucks. He then gives middle fingers to everyone as Luigi, Toad, and Waluigi are arrested and exclaims, "F*** you," with the exception of Fishy Boopkins and his father. He is then shown flipping everyone off while leaving the scene before Mario crashes into him with his kart and gives SMG4 a "F*** you" as the episode ends.