finn and jake stumble across a diary by jiane adventure that explains that she has struggled to survive and is out there somewhere and might not be a chance of surviving any longer.the dark princess has trapped them all in the land of OOO and they can't get out,so they start searching and see if they can find her.they travel all the way to a giant mountain and dodge all the monsters and choose all the right paths(with a little help from the diary)a the nd find finns mother starving and then take her to the treehouse.
finns mom explains that finns dad sacrificed his life for finn and finn got stuck on a leaf in the forest.finns mom barely got out and had to go out on her own in the land of OOO.
It all started when the dark princess was just an ordinary princess in the real world.But then her boyfriend betrayed her and she turned evil with the help from the one and only,CHAOS EMERALD.She turned her boyfriend into a vampire,and trapped him into her make-believe land of dangerous and good things.A land with imaginary creatures and dogs with incredible stretching powers.The land of OOO.
Now,surprisingly,the princess used to be called Princess OOO.That was her parents last name.But she turned her dad into a dream worm and her mom into a snake of wishes and in the parents transformations,they turned evil.
There was only one way to fight the princess back:Her one and only weakness and the only thing that will do harm,the PURE HERO DIAMOND.Only a true hero could witness it's truly awesome power,so it hardly did anything to the dark princess.
The dark princess trapped all the smart and dangerous people into the land of OOO,hoping no one would know of her existence,especially the adventure family.She decided to destroy the baby(finn)once and for all,but finn's dad jumped in the way and sacrificed himself for finn and finn fell into the land of OOO.Finn's mom decided to keep the PURE HERO DIAMOND for later.The dark princess stayed in the real world with slaves.
Finn turns out to be the real hero and has to stop the dark princess,but theres time for that later,because the PURE HERO DIAMOND needs to be recharged with some of its energy and they don't know where to find it.
Jake askes why didn't jianne go to Finn right away to fight the dark princess and jianne answers that she didn't know a thing about where finn was,because they got separated.
THATS FINNS REAL MOTHER.