Board Thread:Spoilers!/@comment-26385535-20160127061149/@comment-24183764-20160127182409

8Rob wrote: I thought they were already back in Storybrooke but it seems I was wrong

Maybe the slippers can travel to the Underworld too, and that's how Zelena meet Hades It's possible that they are back in Storybrooke. The name of 5x14, Devil's Due, makes me think Emma and the others may have saved Hook but it opened a portal or something bringing Hades and some deceased characters along for the ride. We've already seen that deceased characters can spend time with the living.

To be honest there are a lot of theories that make sense.