|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.
"Fionna & Cake Meet Finn & Jake" is a fan-fiction book written by Ice King and was first introduced in Issue 1. In the issue, the book is sucked into the Bag of Holding, when the newly revived The Lich begins his plan to suck up all of the Land of Ooo. The book is likely a sequel to Ice King's first book, Fionna and Cake.