At the end of the last episode, we saw Hook summon all the Dark Ones who ever lived to Storybrooke. Each of the Dark Ones mark all the residents for a trip to the Underworld so that they may stay in their place. Emma is faced with the challenge of saving her family, the town and eliminating the darkness for good for reclaiming Excalibur. And hopefully saving the man she loves before it’s too late.
The mid-season finale begins with a flashback that Killian (Hook) and Regina vowed never to speak of — where we learn that Killian’s father abandoned he and his brother, Liam, and sold them into servitude.
As an adult, still waiting for his revenge on the Crocodile, Hook agrees to kill Regina’s mother, Cora. To prove he’s up to the task, Regina tells him he must first kill a man in a tavern. He is shocked when he sees the man is his father. He expresses his remorse and tells Killian he was under a sleeping curse and was only awakened when his nurse gave him true love’s kiss.
Instead of killing him, Hook agrees to provide transport papers so his father (and his young son) can leave the town. When Hook goes to deliver the papers, he hears his father talking to the boy, Liam (the name of Hook’s dead brother), and ends up killing his father in a fit of rage. As his father dies, he tells Hook, “It’s never too late to change.”
Back in Storybrooke, everyone has been summoned to the lake for the trip to the Underworld. As Nimue begins to choke Emma, Hook decides the man he really wants to be — a hero. He stops Nimue and uses Excalibur to evaporate all the Dark Ones, channeling the darkness inside himself. He begs Emma to kill him so the darkness will finally be gone. She reluctantly does so, and is transformed back to her normal self and Hook dies.
The following day, Emma realizes she can still hear the call of the Dark One’s dagger and confronts Rumplestiltskin. He confesses he never gave them the real dagger to forge with Excalibur and is now, once again, the only Dark One. Realizing that Hook’s sacrifice was in vain and with leverage that she can tell Belle of his trickery at any moment, she makes Rumple promise to take her to the Underworld to save Hook.
They return to the lake to make the journey, only to be joined by Snow, Charming, Regina, Robin Hood and Henry who refuse to let her go alone. And off to the Underworld they go.
“Once Upon A Time” will return in March.