Marceline is on a rampage for mysterious reasons, and the kingdom of Ooo is desperately scrambling to stop her. In trying to save both Ooo and Marceline herself, Princess Bubblegum accidentally propels Marceline into the farthest reaches of space and strips her of her powers! Guilt-ridden, Princess Bubblegum sets off on a space rescue that'll test the power of her mind...as well as the power of friendship.