Titled "The Apprentice," the 4th episode of "Once Upon a Time" Season 4 just aired -- and here are the highlights for those who missed it.

According to ABC.com, the episode began with the sorcerer's apprentice promising that no Dark Ones can ever break a mysterious box and possess the secret stored inside. Forward to the present Storybrooke, Mr. Gold (Robert Carlyle) successfully opened the box by waving his dagger and a magical hat appeared.

According to Entertainment Weekly, the apprentice called himself "Zoso."

Emma Swan (Jennifer Morrison) freed her heart by asking out Hook (Colin O'Donoghue) on a date, and they pushed through. Hook eventually asked Gold to reattach his hand, so that he can perfectly hold Emma. With a word of warning, Gold agreed to bring Hook's hand back, reminding the latter that the hand belonged to the evil, older Hook.

Will Scarlet (Michael Socha) accidentally spilled wine on Emma. Furious, Hook grabbed Will and shortly realized that he was acting differently. He kissed Emma good night.

Terrified at the condition of his hand, Hook came back to Gold and sought aid -- but the latter refused to render help. After attempting to chop the troublesome hand, Hook was convinced that only a form of magic can let it go. Gold unveiled a broom which would take Hook for help.

Rumplestiltskin informed Anna in Fairy Tale Land about her parents; details are out if she agrees to put a substance in an old man's tea, ABC.com continued. This antic turned out to be a trick. Anna threw the liquid into the flames. Rumple revealed that what she dumped was a poison antidote. Anna went extremely shocked as the old man turned into a mouse.

Still, Rumple told Anna her parents' attempts of banishing Elsa's powers. It was revealed that a certain hat, which could take magic away, existed.

The poisoned mouse bit Rumple's hand, and Anna got hold of the dagger the former used to acquire the hat. She took the box away from Rumple, and asked him to bring her back to Arendelle. She met Kristoff and Sven.

Forward to the present day, Hook and Gold were led to the old man / apprentice. Gold waved his dagger once more to produce the hat. Hook gets his hook back. Hypable reported that Rumple gained advantage for believing that he has convinced Emma of his intentions.

Emma chased the Snow Queen (Elizabeth Mitchell) in an icy road, but failed.

As cited in Celeb Dirty Laundry, Henry (Jared Gilmore) went to his grandfather, Gold, asking for an after-school job. Gold handed him the magical broom and told him that he will be working as an apprentice.

"Once Upon A Time" airs in ABC on Sundays, 8/7c.

Watch previous episodes here.