Watch a clip from Once Upon a Time season 4, episode 8, in which Elsa confronts Anna.

Tensions will be running high in Once Upon a Time season 4, episode 8, “Smash the Mirror.” They’ll also be running long, seeing as it’s a double episode!

Through flashbacks we’ll learn more about Anna (Elizabeth Lail) and Elsa (Georgina Haig)’s fallout, which is of course manipulated by the Snow Queen (Elizabeth Mitchell).

But does Anna really end up trapping Elsa in the urn like Ingrid claims? Take a look at this sneak peek released by Access Hollywood, and decide for yourself if Elsa’s outbreak is enough to warrant Anna’s retaliation:

In the clip, Elsa strides into the dungeon to see Anna, who is locked in a prison cell. Anna is relieved to see her, but Ingrid has been feeding Elsa false information about what happened.

And Elsa… believes Ingrid? Somehow we doubt it. The scene ends right when Elsa asks the guards to leave her alone with Anna, so we’re going to make an educated guess and say that Elsa is orchestrating this whole thing to set Anna free, without the Snow Queen realising her plan.

Okay, the promotional images showing the sisters embracing did kind of help clue us in.

Still, we know that Elsa ends up in Storybrooke with no memory of how she ended up trapped in the urn, and what happened to her sister.

Will we get the final piece of the puzzle this week? It’s a two-hour episode, so chances are we’ll get some big reveals, at least.

Speaking to TV Line, Elizabeth Mitchell can reveal one question that’ll be answered this Sunday: how the Snow Queen got to our world.

“It’s really interesting,” she teases. “I thought that it was smart and brought a new element into the whole thing. I think you’ll like it.”

Any theories?

‘Once Upon a Time’ season 4, episode 8, ‘Smash the Mirror’ airs Sunday at 8/7c on ABC.