Once Upon a Time fans will see Snow (Ginnifer Goodwin) and Charming (Josh Dallas) in a crucial flashback in the next episode that may reveal even more about why they are so haunted by their past.

Regina 'Tempted' To Embrace The 'Dark Side' Again on 'Once Upon a Time'

ABC has released a new plot synopsis for the next episode of Once Upon a Time, which is called Best Laid Plans. The synopsis reveals a big flashback that will be revealed in the episode with Snow and Charming making a particular choice that they may just come to regret.

"In a Fairy Tale Land flashback, Snow and Charming search for a way to ensure their child will grow-up to be a hero," the synopsis reads. "When a travelling peddler directs them to visit a kindly old hermit, Snow and Charming are presented with a choice that could secure their child's goodness, but at a price that will haunt them for years to come."

Hook 'Nervous' About Losing Happy Ending With Emma on 'Once Upon a Time'

The child being referred to is Emma (Jennifer Morrison) of course, who will be in grave danger in the present in this episode.

"Hook [Colin O'Donoghue] tells Emma that her fate is at stake in Gold's [Robert Carlyle] plan while Regina [Lana Parrilla] leads the villains on a wild goose chase."

Meanwhile, Henry (Jared Gilmore) is slated to make a big "breakthrough" while searching for The Author, though Snow and Charming "need a moment to reconsider the best course of action."

This is sure to be a jam-packed episode of Once Upon a Time as Snow and Charming's past is further revealed.

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