Finn's awake in his dream - but so is a terrible enemy.
Finn's awake in his dream for the first time since he started drinking himself to sleep five years ago. Luckily, he still remembers what to do: think hard, change the landscape. It's all in his head. It's all under his control.
Except for the man standing in the ocean. He's not in his head. And he's not happy.
He'll hunt Finn down. He'll take his friends. He'll take his family.
And when he gets what he wants, he'll introduce Finn to the real enemy.