The Spell of Shattered Sight has been cast on
and the whole "Fall" episode has mostly everyone concerned with either combating it or getting out of the Snow Queen's way.
First idea: Get out of Storybrooke. The main heroes -- Charming, Snow, Emma, Elsa, Regina and Grumpy -- try going over the wall first. But using brute force against the magical wall of ice -- even just Charming trying to scale it with a pick axe -- doesn't work. The wall fights back, and grows a bit stronger when struck.
So, time to think about survival. Everyone splits up. Regina and Henry go to warn Robin and the merry men. Hook goes to the pier to see if there's a water-bound way to get free of the city. Snow and Charming have to rally the townsfolk, and tell them to do whatever it takes to keep them from hurting each other.
Rumpelstiltskin sees that the Snow Queen has pretty much won. So, being the dealmaker he is, wants to cut his losses and go. He bargains with Ingrid: If she will let him escape the town with his wife Belle and grandson Henry, then he won't spend every waking moment trying to "rip her heart from her chest" once the spell finalizes at sundown. Since Rumpel will most likely be immune to the spell, it seems a reasonable deal for the Snow Queen. She consents.
The studious Belle finds that they can counter the spell if they have something like a lock of hair from someone infected by the curse -- or someone who had been infected by it before. This refuels Elsa's drive to find Anna -- she now knows that Anna must've been under this spell when she put her in the urn. With nothing else to go on, Elsa and Emma are off to find Anna again while Belle and the fairies mix up whatever ingredients they'll need to make the potion.
In past Arendelle, Anna and Kristoff thaw out for some reason -- they're not dead after all! But the wannabe king Prince Hans has come to usurp the throne, and tries to arrest the duo. They escape, and Anna wants to make sure she gets the urn back. The one with Elsa in it. Anna says that they need to find the wishing star, and that maybe a pirate or an evil wizard (Rumpelstiltskin) can help them. Cutthroat pirate vs. evil wizard. Hmmm. Anna reasons that at least you an bargain with a pirate -- they just want money. So, they set out to find one, and they stumble across Blackbeard.
Back in Storybrooke, Rumpel still has Hook's heart. Rumpel orders Hook to help him get the power of the fairies into the Sorcerer's Hat. He needs that power to get he, Henry and Belle out of the magical city limits of Storybrooke with his power intact. If Hook gets the fairies in the hat, there would be no one to finish the curse cure they're working on. Hook gets that Rumpel would sacrifice everyone to be safe, but really, the whole town? "If it's me versus the town, me wins every time."
Regina knows that this spell may turn her back evil, and it's eating her up. As the merry men are breaking their camp and trying to somehow shield themselves from the curse, she and Robin share a moment.
Emma and Elsa, meanwhile, are on the trail of Anna. Elsa miraculously found Anna's locket in the beginning of the episode, and they imbue it with a locator spell. It leads them to the caves beneath the library. Instead of blasting it like Elsa wants to do, they consult Grumpy and the dwarves, who think they can tunnel through safely in a few hours. They don't have a few hours since sunset is coming. Belle says there's a way to do the spell, but it will destroy the necklace -- and, it seems, any chance Elsa and Emma have of finding Anna. So, it's either the town, or finding Anna. After a reasoned and impassioned speech by Regina, they agree that it has to be the town. Elsa gives them the locket, but it's a switcheroo! She keeps the necklace and goes after Anna. Emma then has to go after Elsa, who can't be stopped from blasting through the underground tunnel in the mines and ... coming out on a beach?
Back in past Arendelle, Blackbeard double crosses Anna and Kristoff, handing them over to Hans, who got to him first. Hans now controls all of the money, so she couldn't have paid Blackbeard anyway. On board the Jolly Roger, he has Blackbeard sail out to the point in the ocean where Anna and Elsa's parents probably drowned, and she and Kristoff are pushed overboard in a trunk. But, right before they go over, it is revealed that they were frozen by the Snow Queen for thirty years! No longer is it past Arendelle -- the times have now been aligned.
Elsa is giving up hope that she'll find Anna, and is resolved to face the curse as her punishment for not finding her. Emma can't make her come back to help fight the curse, and it's getting late. Instead, Elsa wishes while holding Anna's star necklace that Anna was with her -- and the wish comes true! Apparently, Anna's necklace was a wishing star. So now, the sisters are reunited!
But, there's still a curse coming -- and the fairies won't be able to help with their potion. Rumpel gets Belle out of the diner, where the counter curse was being created, and Hook, acting on the orders of the Dark One, takes out all of the fairies! They are sucked into the Sorcerer's Hat, despite Hook's reluctance. Anna, Elsa, Emma and Kristoff arrive too late, and not seeing a hidden Hook, think that maybe the Snow Queen took out the fairies.
With no potion to help, the Spell of Shattered Sight settles over Storybrooke and everyone scrambles to protect themselves. Rumpel has locked away and magically protected Belle from any intruders. He retrieves the hat from Hook, and tells him to enjoy his possible last day of not only freedom, but life itself. Regina seals away Henry as well, and also locks herself in her vault of hearts to hopefully shield herself from being forced to become the Evil Queen once again. Robin wants to be with her, but he just doesn't know. Luckily, she pushes him away. Snow White and Prince Charming give baby Prince Neal to Emma, and have her lock them in jail cells so that they won't be able to harm each other or the baby. Kristoff is likewise handcuffed to a sturdy desk. Oh, if it wasn't clear before, it seems that Elsa and Emma, since they have the ribbons and know the Snow Queen wants them whole, and Anna, because she's been cursed before, are immune to the spell.