'Supernatural' Season 13 Episode 21 Spoilers: Sam And Dean All Gear Up To Save Mary And Jack; Gabriel Might Change His Mind About Helping The Winchester Brothers

The much-needed help for Mary and Jack in Supernatural Season 13 Episode 21 is about to arrive. However, there are complications that come along with it.

Jack (Alexander Calvert) is eager to kill Michael (Christian Keyes) more than ever after Kevin (Osric Chau) told him that the apocalypse world's Archangel has no plan to kill him but instead wants to break Jack into pieces. However, it looks like Mary (Samantha Smith) and Jack's situation in the apocalypse world is worsening. Jack could deal with Michael's minions but not the archangel himself. Lucifer's (Mark Pellegrino) son is trying his best to fight Michael, but his power is not enough.

In Supernatural Season 13 Episode 21, titled "Beat The Devil," Dean (Jensen Ackles) is traveling back to the apocalypse world. This time, he will bring Sam (Jared Padalecki), Castiel (Misha Collins) and their new ally, Gabriel (Richard Speight Jr.), along with him.

In the previous episode, Archangel Gabriel agreed to help Sam and Dean in their mission to save Mary and Jack from Michael in the alternative universe. Gabriel was reluctant at first to help out the Winchester brothers as he wants to take his revenge against Asmodeus (Jeffrey Vincent Parise) and all the demigods who sold him as a slave.

Sam and Dean believe that Gabriel, being an archangel himself, has enough power to kill Michael. Gabriel was finally convinced to aid the brothers after Sam and Dean helped him kill Loki and the demigod's sons.

Meanwhile, the Winchester brothers and Castiel will soon realize that they could not trust Gabriel after all. In an interview with Variety, Speight teased that his character is not the same archangel he used to be.

The actor said the torture that the archangel underwent in the hands of Asmodeus (Jeffrey Vincent Parise) changed the character. The actor hinted that Gabriel might have agreed to help the Winchesters in their mission, but he might also change his mind in the end.

"You definitely see an interesting side of Gabriel in those scenes where he basically says "I've been cute for about 15 minutes, I'm done being cute. I don't give a crap about your issues, I've got a problem to solve because I just got my a- handed to me for seven years and somebody's got to pay for that." I think there's something very interesting in the small revelations versus the big blowup. It's about 'This is what I've got to do for me. I may have run, I may have been weak at that moment or made a choice that you didn't approve of - but I didn't set myself up for seven years of torture, nor did I deserve it,' " Speight said.

Moreover, it may not be a happy reunion for the Winchesters when they step through the rift in Supernatural Season 13 Episode 21. The tension between the brothers and their mother will also arise when Mary tells her sons that she intends to stay in the alternate world. It looks like Mary will realize that her true mission in coming back into the world is to save the innocent people in the alternative universe.

Elsewhere, Rowena (Ruth Connell) will still work on the demon tablet. She will soon have an encounter with Lucifer. However, this may have a dire effect on Sam and Dean's journey into the apocalypse world. Rowena and Lucifer are seen in the trailer standing next to the rift in the Supernatural Season 13 Episode 21 trailer.

Supernatural Season 13 Episode 21 will air on Thursday at 8 p.m. EDT on The CW. Check out the Episode 21 trailer below.