An extended synopsis for the upcoming fourth season of ABC's Once Upon a Time has been released, and there is still plenty of drama with the main characters for fans to look forward to.

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 While the Frozen invasion appears to be the buzziest part about the fourth season of Once Upon a Time, it seems that other characters will be having big seasons of their own. For one, Rumplestiltskin (Robert Carlyle) will be in his new marriage to Belle (Emilie de Ravin), but he still has a secret that could see the relationship unravel.

"Rumple is hiding a secret from Belle -- one that, if found out, could destroy their happiness - he continues to be the master of the dagger that calls upon him to be the Dark One," reads an extended synopsis for Season 4, via ABC.

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Meanwhile, Emma (Jennifer Morrison) and Hook (Colin O'Donoghue) are dealing with their own relationship drama as they continue to grow closer.

"Can Emma and Hook commit to one another, and can these two damaged people take their love to the next level?" the synopsis asks, rhetorically. Emma's parents Mary Margaret (Ginnifer Goodwin) and David (Josh Dallas) will be busy raising their newborn, Prince Neal.

Henry (Jared Gilmore) will be "tested" in the new season, having both the good of his mother Emma and the darkness in his paternal grandfather Rumple in his veins.

"Finally, Will Scarlet (Michael Socha, Once Upon a Time in Wonderland), a former member of Robin Hood's band of Merry Men, has traveled across many lands to make his way to Storybrooke. He finds himself intertwined in the goings-on in town for the first time as his mysterious past pushes him to an unknown future."

The synopsis also teases that not every fairy tale character can be trusted, which seems like a no-brainer after three seasons of the fantasy drama.

Once Upon a Time Season 4 is set to premiere Sunday, Sept. 28 at 8 p.m. on ABC.

Tags: Once Upon A Time television ABC