SPOILERS for seasons 1-3.
During an argument, Emma and Regina are pulled through Zelena’s time portal, but instead of ending up in the Enchanted Forest FTL, they wake up in Storybrooke in the year 1987, four years after Regina cast the dark curse. However, the town is not the same town they remember.
While both of them retain their memories, they are thrown for another loop as Emma has been physically de-aged into the body of a four year old and soon starts to get mentally affected, forcing a less than enthusiastic Regina to take charge.
To get back home, the Junior Savior and the former Evil Queen must overcome their differences and find common ground, while facing past demons. Their journey will deliver both of them insights previously overlooked, as Emma will have to learn to trust that someone actually has her best interests at heart, while Regina will be forced to confront the price someone most innocent paid for her casting the dark curse. On top of it all, a danger is lurking in the town, just waiting for a moment to strike.
The story takes place soon after the diner scene at the start of season 4, after Emma unintentionally reunited Robin Hood and Marian.
