If Mario was in... Legend Of Zelda: Ocarina Of Time is the 6th episode of the If Mario was in.... Mario find himself in Hyrule to help Link defeat Ganondorf. It was made to celebrate the release of the latest Zelda game, Breath of the Wild.
Mario takes a trip to Hyrule... and screws up everything.
The episode begins at Peach's Castle, where Mario is playing hide-and-seek outside with Luigi. While Mario tries to look for his brother, he gets the idea to lure Luigi out by exclaiming that Daisy is here and "naked." This does catch Luigi off guard, as the green plumber reveals his hiding spot from inside of a nearby tree. Mario claims that he has won for the fifteenth time in a row; though Luigi tells him that it's because he keeps cheating with random outbursts. As Luigi takes his turn to count, saying that he'll look extra hard, Mario runs off to find a good hiding spot.
He leaves Peach's Castle, Smexy Town, and even The Mushroom Kingdom, until he finds himself in the middle of a random forest. Mario accidently slips off a cliff and lands in another part of the forest: Kokiri Forest. He walks until he finds the forest village, and he is shocked by the new surroundings. Meanwhile, Luigi finishes counting and begins his search to find Mario while the episode's title appears.
Back in Kokiri Forest, Mario makes his way down to the village and spots one of the Kokiris. Thinking they are "Oompa-loompas," Mario tires to blend in until he bumps into Saria, who tries to greet him. Mario tries to act natural by "humping" rocks like one of the Know-it-all Brothers next to him, but he eventually runs off to hide. He eventually comes across a treehouse and goes inside to lie down. However, once he gets in bet and shuts off the like, Mario turns around to find Link sleeping next to him. Link suddenly wakes up, and the two of them scream at the site of each other.
Navi suddenly arrives at the house and tries to wake Link up. Instead she finds Mario in bed, who reveals that he knocked Link out and stuffed him into a nearby trash can. Navi manages to pull Link out and warns him about Mario, whom she classifies as a "fat retarded Italian" that could physically hurt Link with his stupidity. The two of them leave, while an insulted Mario tries to find his own way out. Mario finds the forest exit, but he is stopped by Mido, who refuses to let Mario leave until he's fully equipped. Mario tries a few more times to get around Mido until he resorts to jumping over him.
As Mario enters the Fields of Hyrule, he is confronted by Kaepora Gaebora. The owl tries to give Mario advice for his adventure, although the plumber is not in the mood to listen. After Kaepora finishes, he asks Mario if he needs to hear it again, to which the latter accidentally says yes, forcing him to hear the lecture a second time.
Two hours later, Kaepora is STILL talking, while Mario has fallen asleep. Link comes by and tries to sneak past both of them, but Navi appears and warns Link not to wake Mario up. Ironically, her shouting immediately wakes up the plumber, and Navi pins the blame on Link.
The two of them run off towards Hyrule Castle, with Mario hot on their tail. Navi orders Link to try and shake him off of them by throwing various objects. However, none of the objects seem to slow down Mario. Link eventually pulls out the Kokiri's Emerald and throws it despite Navi's protests. Because Mario is running with his mouth open, the Emerald goes straight in, and he swallows it. Navi demands that Mario throw it up, as they need it to save the world, but Mario refuses. As a result, Navi is forced to drag Mario with her and Link on their quest.
The trio eventually arrives at Hyrule Castle, where they find Zelda in the courtyard. Initially, Mario is the one to greet the princess, which startles her. After a second try, she is introduced to Link, who she believes is the hero from her dreams. While they are talking, Mario is constantly chatting and wandering around in the background, completely bored by the conversation. Navi eventually pushes him out of the way. He is forced to wait next to Impa, whom Mario tries to get the attention of due to her stoic demeanor. After some excessive mocking, Mario does finally get Impa's attention as she throws him over the castle wall. Back in the courtyard, Zelda turns Link towards the window, where she believes someone evil is. It is revealed to be Ganondorf, who dances and holds up a blatant sign saying that he plans on taking over Hyrule.
Mario demands to be let back inside, but nobody listens to him. He suddenly spots Talon standing next to him. As the two of them take a moment to look at their similar features, they both complement each other on their style. Link and Navi eventually exit the castle, and Navi orders Mario to help them gather the other two Spiritual Stones. However, Mario refuses to move because he's too lazy to do so.
Eventually, Link and Navi somehow manage to drag Mario all the way to Goron City. They meet up with Darunia, who asks if they are there to save his people. While Mario insists that he doesn't care, Darunia is convinced that they will take this quest, and he starts to dance as a montage starts.
The trio enter Dondongo's Cavern, and Mario eventually comes across a chest full of bombs, which he becomes a little too trigger-happy with. He uses it to blow up several enemies, even attacking Link at one point. They eventually confront King Dodongo, whom they manage to scare by having Mario ride on top of him, eventually driving him into the lava pit. Afterwards, Darunia rewards the trio with the Goron's Ruby.
Next, they head off to Zora's Domain, where King Zora tells them that the giant fish, Jabu-Jabu, has eaten his daughter. The trio confronts Jabu-Jabu, who inhales them and traps them in his stomach. They find Princess Ruto inside and try to fight their way out, with Mario attempting to use his mustache in the same manner as Link's boomerang, as well as throwing Ruto into pits multiple times. Jabu-Jabu eventually spits them all out, including the Zora's Sapphire. With all three Spiritual Stones now in their possession, Mario, Link, and Navi prepare to head back to Hyrule Castle Town; but not before Mario throws Ruto over a cliff one last time.
Inside the Temple of Time, Link sets the Goron's Ruby and the Zora's Sapphire on their respective pedestals. With the Kokiri's Emerald still inside Mario's stomach, Link sets the plumber on a pedestal as well. The gateway opens, and the trio find the Master Sword inside, lodged in a stone. Link prepares to pull it out in order to save Hyrule. However, he and Navi are caught off-guard as Mario pulls the sword out for himself to use as a butt-scratcher. All of a sudden, the Sage of Light, Rauru, emerges and proclaims Mario to be the "chosen one." Startled, Mario pulls out a pistol and shoots Rauru, killing him. Excited about his new position, Mario rushes out of the temple with the Master Sword with plans to "save deh world," leaving Link and Navi dumbfounded.
However, rather than actually go save the world, Mario starts doing random Zelda activities, such as running around breaking pots, shopping for masks, cutting grass for Rupees, and messing around with Cuccos. After he uses the Master Sword to kill Tingle, Mario notices the sky in Hyrule Field growing dark. Ganondorf suddenly appears, drawn to the power of the Master Sword. Terrified, Mario gives the Master Sword back to Link, who finally confronts Ganondorf. The King of Evil launches an energy ball at him, but Link uses the sword to deflect it. Ganondorf and Link proceed to bounce the energy ball back at each other, with Mario announcing in the background as if it were a tennis match. Link eventually misses and the ball electrocutes him, setting him on fire. Navi grieves over their loss while Ganondorf celebrates.
In his final moments, Link gives Mario the Ocarina of Time. Mario vows to avenge him and confronts Ganondorf himself, attempting to activate the Ocarina's power by playing an off-key cover of "Take On Me", which confuses Navi and Ganondorf, whereas Link appears to like it. However, Ganondorf knocks the instrument out of his hands and breaks it. The King of Evil prepares to attack Mario, but they are suddenly interrupted as Luigi arrives, happily claiming that he has won the round of hide-and-seek. Mario is upset over losing, while Ganondorf is annoyed at the brothers for ignoring him. As a result, Mario forces him to join in their game. Ganondorf reluctantly turns around and starts counting, while Mario sneaks some dynamite up the king's butt and lights it up. The Mario Brothers decide to head home, leaving Navi alone to look at the scene of Link's burning corpse and Ganondorf about to explode. She finally gives up and decides to go get a job working as a lightbulb.
In the epilogue, Bob suddenly appears and demands to know why he wasn't in the story, as he is also from the Legend of Zelda franchise. However, his ranting is cut off as the episode ends.