'Once Upon a Time' is set to return with a promising new storyline. In the recently released trailer, Elsa, the queen from the hit Disney movie 'Frozen', leaves an icy trail around the town wherever she goes. The trailer starts with a narrative voice, "This September, winter comes early. When the town of Storybrooke gets frozen over."

According to Christian Post, besides Elsa, the entire cast of the 'Frozen' movie will also join the cast of 'Once Upon a Time'. Elizabeth Lail will play Princess Anna, Scott Foster will play Kristoff, Tyler Moore will play Prince Hans, and John Rhys-Davies will play Pabbie, the Troll King.

Also, Kristen Bauer Von Stratten will play the role Maleficent as confirmed by Entertainment Weekly. However, there is still in doubt whether Kristen comes in as a regular on the show or not.

Other than the new characters introduced in the latest season, we will also see the return of some familiar faces on the show. According to sources, Robin Hood, Belle (Emilie de Ravin), Rumple (Robert Carlyle), Neal (Michael Raymond-James) and Zelena (Rebecca Mader) will return to the show.

According to TVLine, there might be a love interest appearing for Henry (Jared Gilmore). ABC is apparently looking to find someone who can play "Lily." Lily is described as a self-reliant, smart and charming teen. She is also very secretive and insecure. Christian Post stated that the recurring character, Lily, is set to appear in the fifth episode in the upcoming season. However, fans are left wondering why she comes to Storybrooke in the first place.

'Once Upon a Time' Season 4 will return on ABC on Sunday, Sept 28.