With only three episodes left before the explosive finale of "Supernatural" season 13, the story has begun to shift to the current season's main focus, which is the Apocalypse world. In the upcoming episode 21, Sam (Jared Padalecki) and Dean (Jensen Ackles) Winchester will be more ready this time to travel to the Apocalypse dimension as the brothers now have an archangel by their side to defeat the enemy.

According to the official synopsis of "Supernatural" season 13 episode 21, titled "Beat the Devil," the Winchesters finally recruits Gabriel (guest star Richard Speight Jr.) in their team as they plan on going to the Apocalypse world to save Mary (Samantha Smith) and the Nephilim, Jack (Alexander Calvert). Together with Castiel (Misha Collins), Sam and Deal will attempt to open a rift to the Apocalypse world.

To recap, Sam told his brother that he will not allow him to go to the rift all by himself, worried that he will lose his brother once again. The two are determined to enter the Apocalypse world together, knowing how dangerous that place is with a mischievous archangel lurking. Although, they now have a better chance to survive the mission as the Winchester have finally convinced Gabriel to fight the Apocalypse Michael (Christian Keyes). In the previous episodes, Gabriel was reluctant to help out Sam and Dean as he was busy plotting his revenge against Asmodeus (Jeffrey Vincent Parise) and all those demigods who sold him to the prince of Hell as a slave.

In order to get Gabriel to their side, the Winchester brothers agreed to help the archangel carry out his revenge. After saving Gabriel from his enemy, it became clear to the latter that Sam and Dean are on his side. With this, he has decided to join them in their quest to the Apocalypse world. Being an archangel himself, the Winchesters believe that Gabriel has enough power to kill Apocalypse Michael, thus stopping the apocalypse from befalling the real world.

The spoilers for "Supernatural" season 13 episode 21 also reveals Mary and Jack's worsening condition in the Apocalypse world, although Jack will try his best to defeat Apocalypse Michael by all means. For now, his power is just enough to kill the lesser minions, but Jack is still nowhere near the level of Michael.

"Supernatural" season 13 episode 21 will air on Thursday, May 3 at 8 p.m. EDT on The CW.