Once Upon A Time Season 4
Cruella will kidnap Henry in Once Upon A Time season 4 episode 19 OnceUponATime/Facebook

Next week's episode of Once Upon A Time will centre around Cruella de Vil (Victoria Smurfit) and her villainous plans.

Episode 19 is titled Sympathy For The De Vil, and will air on 19 April at 8pm on ABC Network.

According to the official synopsis, "In fictional 1920s England, viewers meet a young Cruella, whose oppressive mother uses her Dalmatians to terrorize her daughter. Cruella is confined to her mother's attic until a mysterious stranger arrives and empowers her to challenge her captor."

Meanwhile in Storybrooke of the present, "Regina gains leverage to keep Gold from interfering with her plan to rescue Robin, but her trip to New York takes the backseat when she and Emma learn that Cruella has kidnapped Henry."

Going by a new promo released, Cruella will go to any length to secure her happy ending.

"Today is the day I get my happy ending" she declares in the promo.

The 30-second video shows the Queen of Darkness kidnapping Emma and Regina's son Henry.

"You will do exactly as I say" Cruella says, as the promo shows the two mothers do whatever it takes to get their son back.

The promo ends with Emma shouting "let him go."

"Come any closer and he dies" replies Cruella pointing a gun at Henry.

Last week's episode also revealed that Robin Hood's wife Marain is actually Zelena. It turns out when Rumple "killed" Zelena last spring in the Storybrooke jail cell, her "life force" floated over to the barn where that portal had formed. As such, when Emma and Hook entered the portal, she went along for the ride to the Enchanted Forest of the Past.

Once there, Zelena used the glamour spell to replace Marian, whom she vaporised. As such, the 'Marian' that Hook and Emma brought back to Storybrooke was Zelena all along. Her original plan was to rob Regina of her happy ending by getting Robin to fall back in love with 'Marian,' but she ultimately realised that wasn't going to work.

But now, Zelena uses the leverage she has to make Rumple add her own happy ending to his list of requests for the Author.