A battle-weary Finn returns to a familiar kingdom only to find that it’s under the control of a snake-headed tyrant, whose master plan will have devastating consequences for all of Ooo. In order to save the day, Finn will need the help of friends, rivals, and especially his beloved brother Jake the Dog. But there’s just one problem. He hasn’t seen his brother in years! Not only will Finn have to find Jake before it’s too late, he’ll have to convince him to return to action for one last adventure together.