Board Thread:Spoilers!/@comment-26109288-20151219143455/@comment-6175354-20151221032311

Everthevillain wrote: I hightly doubt that will be the central, and sole plot of the 5.B arc. Going to the Underworld to save Hook, is probably just the lead-in for a much bigger story.
 * The point of 5B is to find Hook split a heart and get out

Eddy and Adam said, that this half will be about giving the characters closure, for things that happened in their past. They also said, that the two arcs will be connected, and serve as one whole story.