As season 4 of "Once Upon A Time" draws to a close, viewers will see Emma step into the dark side. After pushing Cruella de Vil off a cliff to save Henry, the savior of Storybrooke strikes Snow White and Prince Charming with horror when they realize that their daughter took away the Dalmatian kidnapper's life. 

Executive producer Adam Horowitz admitted to TV Line that "Emma has crossed a line," calling her an "ever-unseemly Savior" for killing Cruella in cold blood as well as her "riff with the 'rents." 

Next week's episode titled "Lily" will be all about Emma's reunion with her old friend. Unfortunately, it's not the kind of reunion that's about hugs and kisses but one that may end up with one of them dead. However, the executive producers of the series reveal that it "is not all deathly conflict." 

"There are moments of warmth and there are moments of bonding. And there's a lot of emotion. It's a real story of friendship," executive producer Eddy Kitsis told TV Line regarding how things will go down between Lily and Emma in the upcoming episode. 

In a promo for the installment, fans are shown flashbacks of Lily and Emma in foster care. A voice narrates that the next time the good friends will see each other will be as mortal enemies, teasing that the girls' fate are "intertwined." 

And although Lily is determined to "punish" Emma's parents, the savior will attempt to help her out. The synopsis for episode 20 reveals that Emma will end up helping Lily reunite with her mother Maleficent. However, there will be a lot of fighting before that happens. 

In her mission to bring the mother and child together, Emma will have Regina, who has her own troubles, by her side. The next episode will see the Queen warn Hood about Zelena. Regina will also use Belle as a leverage to thwart any more of Rumple's plans. 

"Once Upon A Time" season 4 episode 20 will air on April. 26.