|The following information is from the Adventure Time comic book series. It may not be part of the same canon or continuity as the animated series.|
While trying to hold off the robots, Finn, Jake, and QB hide out in Marceline's cave.
At Queen Bubblegum's laboratory, Finn and Jake and Bubblegum begin to be attacked by evil robots. Using Tank Legs as a bomb, Finn, Jake and Bubblegum escape the Candy Kingdom with seconds to spare. The Candy Kingdom explodes, killing all the evil robots inside, but more are on the way.
Finn, Jake, and Bubblegum come across Choose Goose, who offers to sell them a sword that can help destroy the evil robots for 50 gems. Finn only has 49 gems, so Choose Goose does not sell it to them. Finn and Bubblegum decide to run to Marceline's cave, while Jake stretches himself huge to fight off the incoming evil robots. After getting to Marceline's cave, they seal the door which gives them ten minutes until the robots break in.
Finn then comes up with an idea to put all the heavy lifting on their future selves; the three swear to spend the rest of their lives working on time machines to send back to that exact moment, which they will then use to go back in time to stop the evil robots from happening. A time machine teleports into the cave with two seats and a note saying that Bubblegum should stay behind and not travel back with Finn and Jake. After hugging, Bubblegum kisses Finn and tells him that six years is not such a big deal when they are older.
Finn and Jake use the time machine to go back in time, while Bubblegum sits and waits, when suddenly a giant robot hand crashes through the cave's ceiling. BMO is controlling the giant robot and says that it has finally come up with a way to defeat the evil robots, all they need is giant robot suits. After Bubblegum tells BMO that Finn and Jake that they've already gone back to fix everything, they use giant robot suits to destroy the evil robots while they wait.
Happy Birthday Hot Dog Princess
For Hot Dog Princess's birthday, Princess Bubblegum agrees to grant her one birthday wish. Hot Dog Princess asks to be united with her long lost bun one last time. Princess Bubblegum delegates this task to Peppermint Butler. They travel to the Land of the Dead and HDP reveals that her bun is her prince. They ask that Death release HDP's bun. Death agrees, but only if Peppermint Butler "pay[s] the price." Peppermint Butler's candy melts revealing his skeleton and the two go to retrieve HDP's bun. Upon reaching him, he says that he wants to stay because he has everything he could ever want. HDP angrily leaves and apologizes to Peppermint Butler for causing his candy to melt for nothing. Peppermint Butler assures her that his candy will grow back and ominously states that they will return to finish what they started.