Finn and Jake race to the Candy Kingdom. When they arrive, they find Princess Bubblegum in her lab, sulking. "Guys! Thank Glob!" the princess exclaims. "Peebles! We got your note and-" Finn started. Bubblegum cut him off. "Just come with me." She replied. Bubblegum led Finn and Jake down a dark and damp hallway. "Yuck." said Jake. "It smells down here." Bubblegum didn't respond. She pulled a silver key out of her lab coat. "Oh my glob." said Finn, shocked.
A man was sitting on the floor, absentmindedly playing with his crown. "Oh." said the stranger, standing. "I know you must be confused, Prince Gumball." said the princess. "How do you know my name?" asked Gumball. "All in good time." replied Bubblegum. "Now let me explain." She said, addressing all of them. "Apparently, Ice King has been writing fan fiction about our lives." Jake laughed. "What a loser!" "Anyway," said Bubblegum. "He loved his stories so much, he made a spell to make them real. He didn't know he was messing up another world. The land of Aaa, right?" She turned to Gumball. "Yeah." He said. "So why is this bro here?" asked Finn. "The Ice King's stories were in reversed genders. Gumball here was just looking for his Candy Kingdom, and ended up finding mine." "There's still one thing I don't get." said Finn. "Why aren't the reversed genders of Me and Jake here?" "Well, most likely they went to find the Tree Fort, thinking it was theirs, and not yours." "One other thing." said Jake. "Why aren't their reversed genders of all the candy people running around?" "I think Ice King only made the people who he writes about most come into Ooo." said PB. "Glob man!" said Finn to Jake. "That means their's girls at the Tree Fort!" "AHHHHH!" Yelled the boys in unison. Then they ran off to their home. "Well, how are we going to get you back to Aaa?" Asked Bubblegum to Gumball. "I think with our two brains, we could whip up a portal easy peasy!" exclaimed Gumball.
When Finn and Jake reached the Tree Fort, the found a girl and a cat playing with BMO. "What are you dudes doing in our house?" asked the girl. "EXCUSE ME, but the last time I checked, this is MY house." said Finn. Jake nudged him. "OUR HOUSE." The cat stood up. "Your gonna get your eyes clawed out if you sass my girl Fionna again!" Jake growled. "Wait, is your name FIONNA?" "Yeah..." said the girl. "Why?" "That means your our swapped genders!" Then they explained what Bubblegum had explained to them. "We have to go get Marshall Lee!" said Fionna to Cake. "Is that the boy version of Marcy?" Asked Finn. "I guess so!" shouted Fionna. They both climbed onto their animals and rode off to Marceline's cave.
When they got their, they found Marcy and Marshall having a fight about who's cave was who's. "STOP!" Yelled Finn, and one again explained how all of this happened. Marcy and Marshall stopped fighting, and turned into their own separate bat-monsters. The gang all raced back to the Candy Kingdom, where the Ice King was waiting.
He had turn almost half the Kingdom to ice. Candy Kids were screaming and trying to find parents. Parents were looking for shelter. "GLOB!" Shouted Marshall Lee. "This guy must be The Ice Queen's gender bender!" "Yeah!" shouted Fionna and Cake. "All right here's what we do..." started Finn.
Once they were all in position, Marceline shifted into her monster, and tapped Ice King on the shoulder. Then, she stole Gunter. Ice King started to throw snow at her. That's when Marshall swooped in and stole the crown, releasing Ice King of his powers. Next, Finn on Jake and Fionna on Cake, came in to beat up Ice King until he retreated to his kingdom saying, "YOU WILL BE MINE, FIONNA!!!"
When they finally made it into Bubblegum's lab, she and Gumball had made a portal. "In, In! Before the portal to Aaa closes!" Shouted Gumball. He turned to Bubblegum. "Thank you for everything. Let's open the portal again sometime." He smiled, and kissed her cheek. She was all blushies. "Later bro. Lets play some music together sometime. This one time, my mom, the Queen of the Nightospere, ate my fries, and wasn't even sorry! I'd love to sing about that!" Marcy laughed. "You have no idea." Marshall entered the portal after Gumball. "Bye!" said Fionna. She gave Finn a bone crushing hug. "Later Cake. If I didn't have a girl, we could go out." said Jake. Cake gave him a hug. "The land of Ooo wishes you safe travels!" Shouted Bubblegum just before the portal closed. "Come here Finny....." said a cackling female voice. Finn turned around, only to be face to face with the Ice Queen.