Welcome to Storybrooke - S2-E17
Continuity mistake: When Henry is at the wishing well, intending to blow it up, his backpack keeps moving around throughout the scene. In some shots, it's lying on the ground by the pedestal, in one shot, it's lying on the pedestal, next to the well, and in other shots, it's gone completely. (00:34:20)
Welcome to Storybrooke - S2-E17
Revealing mistake: After Regina burns the curse that will make Henry think he loves her, when Henry walks over to Emma and the others a few shots later, Regina has the curse scroll in her hand again. (00:36:40)
Welcome to Storybrooke - S2-E17
Continuity mistake: When Greg Mendell bumps into Henry in the woods, Henry drops his backpack on the ground, the backside facing upwards. When Greg picks it up, the front is facing upwards. (00:28:40)
Welcome to Storybrooke - S2-E17
Continuity mistake: When Henry is in the forest while it's raining, his hair keeps changing, especially his fringe. (00:28:20)
Welcome to Storybrooke - S2-E17
Continuity mistake: When Kurt and Owen are in the diner, in the first shot, Kurt is holding his tankard of beer by gripping the top. In the next shot, he's holding it by the handle, and the vegetables on his plate have changed position. (00:11:55)
Welcome to Storybrooke - S2-E17
Continuity mistake: In Mary Margaret's apartment, when Emma is having breakfast with her family, after she says "He deserves to know", her right arm is resting on the counter, next to the bowl of cereal. In the next shot, both of her arms are resting in her lap. A spoon in the bowl also changes position. (00:10:25)
Welcome to Storybrooke - S2-E17
Continuity mistake: When Emma is having breakfast, the amount of cereal in the bowl in front of her keeps changing. (00:09:55)
Welcome to Storybrooke - S2-E17
Continuity mistake: During breakfast in Mary Margaret's apartment, there are two plates of toast on the bench. The distance between the plates changes between different camera angles. In some shots, they are right next to each other; in others, there is a gap of approximately 30 centimeters between them. (00:09:55)
Welcome to Storybrooke - S2-E17
Continuity mistake: Baelfire/Neal is in the diner and wraps his scarf around his neck while Emma walks over to him. Then the camera is on Emma and you can see Baelfire/Neal moving as he puts the scarf on. Seconds later the camera switches back to Baelfire/Neal and he wraps the scarf around his neck a second time. (00:25:05)
Answer: He knows who she is because he knows that the fairy tales are true. He was also shown to sneak out to go see Emma or someone else. Sometimes he succeeded, sometimes he didn't. This is how he knew to look for her despite his strict mother.