'Supernatural' season 11 episode 21 spoilers: The Winchesters attempt to save Castiel from The Darkness

Dean and Chuck in Supernatural season 11 episode 21.YouTube/The CW

The Winchester brothers will act fast to save their friend in the upcoming episode of "Supernatural" season 11.

In the episode titled "All in the Family," Dean (Jensen Ackles) will discover how Amara (guest star Emily Swallows) tortures Lucifer (Misha Collins). Since the fallen angel is using the body of their closest friend Castiel (Collins), Dean and his younger brother Sam (Jared Padalecki) must come up with a scheme to rescue him from The Darkness.

Based on the trailer for the upcoming episode, Dean will persuade novel writer Chuck (Rob Benedict), believed to be God himself, to help them stop Amara from her evil plans.

In an interview with TVLine, Benedict talked about his character's role in the Winchesters' fight against Amara to rescue Castiel.

"We all have the same goal — we want to try to stop her," the actor said. "We have different reasons for why, but ultimately, what we have to do is be on the same team and trust each other."

Benedict also explained how Chuck planned to work with Sam and Dean to win over The Darkness.

"First on my plate as God is to get them to trust me, because I need them to be my boots on the ground, and we need to work together again. But I feel like there's always been a lot of love there between Chuck and the boys, and that's definitely highlighted in this next episode," the actor added.

The actor also teased God's possible reunion with the angels after he opted to abandon them. According to Benedict, God needs to have a conversation with the angels, including Castiel, to explain his reason for leaving them on their own. He also needs them to trust him again.

The 21st episode of "Supernatural" season 11 will air on Wednesday, May 11, on The CW.