'Once Upon A Time' season 4 spoilers: Emily and Lily's reunion may not be as happy as expected in episode 20

ABC

Emma will finally see her childhood friend again, but it was not the happy reunion that was typically expected.

In the upcoming episode of "Once Upon a Time" Season 4 episode 20, Emma (Jennifer Morrison) will finally encounter her closest friend from childhood Lily (Agnes Bruckner), who happens to be the long-lost daughter of Maleficent (Kristin Bauer van Straten).

Their lives crossed paths when they were staying in the same foster home in the world outside of Storybrooke, but it actually goes beyond that. Emma's parents Snow White (Ginnifer Goodwin) and Prince Charming (Josh Dallas) happened to be the reason why Lily had to be separated from her mother, to be able to ensure that Emma will not have a dark side when she grows up.

But when the Emma and Lily saw each other again in the present day, things had changed between the two.

Emma had to work with Regina (Lana Parrilla) to find Lily first before she managed to plot a revenge on the people responsible for her separation with her mother, but at the same time, the unlikely pair will have to find Robin (Sean Maguire) about the possible danger that Zelena (Rebecca Mader) can bring. However, both Emma and Regina will also be facing a lot of difficult real world challenges that none of them were prepared for.

Elsewhere, Gold (Robert Carlyle) will face his own troubles in Storybrooke. This time, he had to sort out things with Belle (Emilie de Ravin).

Meanwhile, series co-creator Eddie Kitsis teased what lies ahead in the upcoming season finale of Once Upon a Time season 4. In an interview with TVLine, Kitsis shared: "We make good on what Regina was after, in the sense that she wanted to find the Author and have him rewrite endings ... Usually we're like, 'Hey, we're going to a new land,' but this is much more in the vein of when Gold looked up (at the end of Season 1) and said, 'Magic is coming,' where a condition on the show changed as opposed to the characters changing."

Once Upon A Time Season 4 episode 20 is slated to air on Sunday, April 26.