The ramifications of Hook being turned into a Dark One by Emma are explored this week on Once Upon a Time. As it has done all season, the episode flips between the present and the group’s time in Camelot to reveal how Hook dealt with being rescued from death, only to be turned dark.
Let’s just say Hook is not happy, as the story unfolds in Camelot, to be sharing the Dark One name with Emma. He tells her he spent centuries shedding the darkness from his heart only to have her bring it back to him. Emma’s supposed betrayal, lying to Hook about possessing Excalibur, fuels Hook’s fury in Camelot. This is what brings about Hook and everyone else losing their memory.
Hook seeks out Merlin to enact a curse to bring them back to Storybrooke. To protect himself, as Excalibur is the only thing that can kill him, he sends it back to the stone. Merlin tells him a spell to return them back to Storybrooke requires the heart of someone Hook loves. Hook finds a loophole, summoning Nimue and saying she is him and he is her — as they are all one as the Dark One — and crushes Merlin’s heart, killing him.
Emma sees what Hook does and wipes his memory, storing his memories in a dream-catcher, saying she wants to return him to the man he was. To protect him and what she has done to bring him back to life, Emma adds to Hook’s curse, blanking everyone’s memory. The curse catches all the Storybrooke residents along with Arthur, Guinevere and Merida.
Back in Storybrooke, Emma works with a hesitant Henry to find the dream-catchers Hook stole to restore their memories. They find them in the clock tower but Emma can’t get to them thanks to a protection spell she can’t break since Hook and Zelena put the bracelet used on Zelena to neutralize her magic on Emma.
Henry, believing Emma is trying to change, uses a potion to take off the bracelet and Emma retrieves the dream-catchers.
Meanwhile, Gold faces Hook with only a sword. They fight on Hook’s ship and Hook wounds Gold with a cut to the shoulder. Gold does best Hook, standing over him with Excalibur, but Hook uses magic to get away.
The episode ends with everyone getting their memories back, including Emma, who now knows what Hook is up to. What is Hook up to? He has used the blood of Gold, who has been to hell and back, to open the portal to the underworld. He does this to summon all the Dark Ones and bring them back in the flesh.