Once Upon a Time
Will Regina tempted back to join Queens of Darkness in 'Once Upon a Time' season 4 Episode 15 titled 'Enter the Dragon'?Facebook/Once Upon a Time

"Once Upon a Time" Season 4 Episode 15 titled "Enter the Dragon" will revolve around Evil Queen Regina Mills (Lana Parrilla), Queens of Darkness Maleficent (Kristin Bauer van Straten), Ursula (Merrin Dungey) and Cruella de Vil (Victoria Smurfit), Belle (Emilie de Ravin), Rumplestiltskin (Robert Carlyle) as well as Mary Margaret (Ginnifer Goodwin).

As per the official synopsis of ABC's fairytale drama, Regina will begin an undercover operation in order to infiltrate the Queens of Darkness. But it will not be an easy task for the Evil Queen as she must prove her willingness to get her hands dirty.

In the trailer of "Enter the Dragon", Regina meets Queens of Darkness and tells them, "You know how much I wanted my revenge. But in this town I had played nice to survive alone watching them enjoying the happiness that I was denied. If you are planning to destroy that happiness, I want in."

However, Maleficent, Ursula and Cruella de Vil do not believe her and try to find out the truth by giving her truth potion. After consuming it, Regina tells them that she is worst than the Queens of Darkness.

Although the clip indicates that she is tempted to be back to the dark side, executive producers Edward Kitsis recently revealed that the Evil Queen will put her life in danger during her undercover operation.

He also teased that Pinocchio aka August Wayne Booth (Eion Bailey) could have more screen space in the upcoming episodes of "Once Upon a Time" Season 4. "We are going to dive more into the backstory with what happened with him writing pages in the book and why he was doing what he was doing," Kitsis told Entertainment Weekly.

On the other hand, Margaret, David Nolan (Josh Dallas) and Emma Swan (Jennifer Morrison) will keep a track of Regina's undercover operation. Meanwhile, Captain Hook (Colin O'Donoghue) will reach out to Bell for a favour as Henry Mills (Jared S. Gilmore) makes progress on his search for the Author.

In a Fairy Tale Land flashback, Regina befriends Maleficent and helps her to rekindle her lost spark and earn her trust in the upcoming episode. 

ABC will air "Once Upon a Time" Season 4 Episode 15 titled "Enter the Dragon" this Sunday, 15 March, 8pm. The show will be live streamed here.