Once Upon a Time returns Sunday with “The Doctor,” and in this sneak peek you can see how Emma, Snow, Mulan and Aurora meet Captain Hook.

In the clip we see that Hook (or Killian Jones) is tied to a tree, and begging the foursome to free him because he is “just a blacksmith.” But Emma doesn’t buy it, of course, with her (probably magical) ability to tell when people are lying.

He admits to them that he is Captain Hook, who Emma recognises from stories. But Mary Margaret also seems to know him, and is shocked when she pulls the hook out of his satchel.

How does Hook’s reputation precede him, if Snow is so shocked by his appearance? And how and when did he get from Neverland back to the Enchanted Forest? We can’t wait to find out why he’s working with Cora, and what they are planning.

If you missed it, also check out the first sneak peek released from “The Doctor,” which features Doctor Whale and David in Storybrooke, discussing whether fairytale land still exists.

This is the episode in which we’ll finally learn the identity of Whale, and judging from this promo, it looks like he’s Frankenstein! Were you surprised by this revelation?

Once Upon a Time airs Sunday at 8/7c on ABC.