The story takes place 4 years later and Marceline has been kidnapped by ash but Finn comes to find her what will happen as marceline finally sees her long awaited hero.

My name is (y/n) (l/n) and I have no idea how I came here to the underground. No, really, I just woke up in a patch of flowers... Anyways, I've heard legends about monsters that live underground... They exist. But something about them is just... Odd... I've heard from monsters that the king is obsessed with us humans and well... I'm not really sure how to feel about that... In this book, you are going to read my adventures from when I travelled through the terrifying city's full of monsters who... All... Love ME?!?