Revealing mistake: In the first shot of the scene where Emma and the others arrive in Storybrooke in their cars, on the left side of the screen, you can see a sign behind a branch. It says "Steveston Museum and Visitor Centre." Steveston is the name of Canadian town which doubles as the town of Storybrooke on Once Upon a Time. (00:07:00)
Deliberate mistake: Elsa's dress in Season Four is different from the dress she was wearing in the Season Three finale. The new dress is a different shade of blue, and has a completely different design, even though the present day events of Season Four take place mere moments after the end of Season Three.
Revealing mistake: In real life, the Storybrooke Cannery is known as the Gulf of Georgia Cannery, a real cannery in Steveston village, the town which doubles as the town of Storybrooke on Once Upon a Time. In most episodes where the cannery appears, the name on the building is replaced with the Once Upon a Time version. However, in this episode, when Emma is driving in her father's truck following shortly behind Cruella's car, there is a wide shot of Cruella's car turning right, and you can see the sign on the cannery, which has not been updated properly: Bizarrely, the first word of the real business name is still on the building, and the first three letters of the fictional name are missing, making the name on the building "Gulfrybrooke Cannery." (00:23:20)
Revealing mistake: When Regina is waiting outside the Storybrooke Library, there is a wide shot of Cruella's car making its way down the road. On the building on the right side, you can see a large vertical sign on the side of the building, which lists several local businesses. If you read the top of the sign, you can see that it says "Steveston Hotel." Steveston is the Canadian town which doubles as the town of Storybrooke on Once Upon a Time. (00:20:45)
Continuity mistake: The flashback scene where The Snow Queen takes Emma's video camera away from Kevin differs from what is seen on the video recording of that moment in "Breaking Glass" and "Family Business." For example, in the recording, Ingrid says, "We respect property in this house, Emma." In the actual scene, she says, "We respect property in this household, don't we, Kevin?"
Revealing mistake: When Snow White and Prince Charming hurriedly make their way through the woods in the beginning of the episode, in the shot where Snow White jumps over a log, you can see the face of Ginnifer Goodwin's and Josh Dallas' stunt doubles. Josh Dallas' stunt double can also be seen as Snow and Charming are running thought the woods in the previous shot.
Revealing mistake: After Mr. Gold's group leaves Mary Margaret's apartment, in the wide-shot where Mr. Gold asks Cruella and Maleficent to follow Regina, a direction sign pointing to a shop called "Steveston General Store" can be seen on a building. Steveston is the Canadian town which doubles as the town of Storybrooke on Once Upon a Time. (00:14:30)
Revealing mistake: When Mary Margaret and Regina engage in a sword fight in the sheriff's office, in several wide shots, the faces of Ginnifer Goodwin and Lana Parrilla's stunt doubles are visible. For example, in the wide shot where Regina is bending Mary Margaret across the desk and David says, "Careful", Lana Parrilla's stunt double is seen. (00:30:20)
Revealing mistake: During the car chase scene, when Lily is driving Emma's car, there are several wide shots of the car driving down the road and you can see that the one driving is not Agnes Bruckner, but her stunt double. Lana Parilla's stunt double can also be seen in several wide shots when Emma and Regina catch up with Lily and try to overtake her. (00:30:55)
Continuity mistake: When Elsa is walking down the middle of the street through Storybrooke, she is leaving a trail of ice on the road behind her. Shortly after seeing a wedding dress in a store window, she walks towards the store, and the trail of ice behind her is gone. (00:07:00 - 00:07:35)