the vampire king 'marshall lee x reader'

(Y/n) lived with Finn and Jake doing whatever they can. But when Princess Bubblegum sends them to a quest to shut down a 'dangerous' portal, (Y/n) is pushed in and put into what seems like the same place. Stuck in the forest and walking for what seems like forever, she hears music playing and sees what looks like Finn but only...female? Then she spots the bad little boy