Emma (Jennifer Morrison) and Regina (Lana Parrilla) are together again on the next episode of ABC's Once Upon a Time, putting aside their differences for a common goal.

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Regina's heart was broken when Emma inadvertently brought Robin Hood's (Sean Maguire) lover Marian (Christie Laing) back from the past at the end of the third season, and they have mostly been at odds ever since. However, they will team up to find the Snow Queen (Elizabeth Mitchell) in the next episode of the series, titled Breaking Glass.

Morrison spoke with TVLine about this episode and how Emma will do her best to regain some trust again.

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"You're going to see Emma really fight to prove to Regina that she wants to be a friend, that she wants to have a good relationship with her," Morrison previewed.

As OUAT co-creator Adam Horowitz previously said at New York Comic-Con, this storyline is a throwback to the beginning of the series when Emma was the hero and Regina was the villain.

"The show really did start on the conflict between the two of them, and their growing and changing relationship... and there is an episode where we explore that. It takes off from the idea that we saw in the [season] premiere, that Emma [as Savior] has to bring everyone a 'happy ending,' including Regina," he said.

It remains to be seen if Emma and Regina will regain their friendship or if they are doomed to be at odds with each other.

Once Upon a Time airs Sundays at 8 p.m. ET/PT on ABC.

Watch the promo for the next episode of Once Upon a Time here:

Tags: Once Upon A Time television ABC