A number of story lines will be juggled in the Season 4 premiere of Once Upon a Time, including insight into Frozen's Queen Elsa (Georgina Haig), some drama between Emma (Jennifer Morrison) and Hook (Colin O'Donoghue) and an unhappy Regina (Lana Parrilla).

Frozen's Elsa & Emma Ready For Some Blonde Bonding on Once Upon a Time

ABC sent out a press release Monday for the Season 4 premiere episode, which is titled A Tale of Two Sisters. The episode introduces Elsa to Storybrooke as it also delves into her past.

In the premiere episode, "a scared and confused Elsa finds herself in Storybrooke and, fearful of the intentions of its residents, creates a powerful snow monster for protection," according to the press release.

Elsa Waltzes In To Storybrooke In New Once Upon a Time Trailer, Regina Quips, 'Here We Go Again'

The episode will feature a flashback to Arendelle of the past with Elsa's sister Anna (Elizabeth Lail) discovering some new secrets about their dead parents. While Anna is set to marry Kristoff (Scott Michael Foster) very soon, she finds out that her and Elsa's parents were on a quest "that may have held the secret to containing Elsa's out of control Ice powers." Anna wishes to "finish their journey" in order to find out exactly what they were looking for.

As for the show's main characters, there will be a lot of relationship drama in the premiere. Regina will be reeling from Emma bringing Robin Hood's (Sean Maguire) wife Marian (Christie Laing) back from the past. In the premiere, she will be wondering "if her 'happily ever after' with the former thief has been completely quashed." Hook will feel that Emma is avoiding him while she comforts Regina over the incident.

Meanwhile, Mr. Gold/Rumple (Robert Carlyle) and Belle (Emilie de Ravin) are on their honeymoon and the former discovers an "intriguing object that makes him question whether or not he should officially give Belle control over the dagger that makes him The Dark One."

It all comes together when Once Upon a Time Season 4 premieres Sunday, Sept. 28 at 8 p.m. ET/PT on ABC.

Tags: Once Upon A Time television ABC