Everything we know about Supernatural season 13 episode 21.
 
The official press release
 

SUPERNATURAL
“Beat the Devil” — (8:00-9:00 p.m. ET) (Content Rating TBD) (HDTV)


THE LONG JOURNEY HOME – Sam (Jared Padalecki), Dean (Jensen Ackles), Castiel (Misha Collins) and Gabriel (guest star Richard Speight, Jr.) must work together if they have any hope of bringing Mary (guest star Samantha Smith) and Jack (Alexander Calvert) home. Meanwhile, Rowena’s (guest star Ruth Connell) encounter with Lucifer (Mark Pellegrino) may alter the outcome of the journey for one of our heroes. Phil Sgriccia directed the episode written by Robert Berens (#1321). Original airdate 5/3/2018.

Source:

The CW

 
 
 
 

From TV Line

I want Dean back on Supernatural — the good ol’, protective big brother Dean. Please tell me we’ll get some great brotherly moments soon! —JJ
Remember how star Jared Padalecki told us Sam would go through something “pretty harrowing and terrifying” in this Thursday’s episode? Well, Dean has a very emotional, big brother reaction to it. On the lighter side, you can look forward to some comedic scenes as the brothers, Cas and Gabriel awkwardly land in apocalypse world — let’s just say personal space is invaded — and Rowena does something that leaves the boys’ mouths agape.

 
 
What can you tease about Thursday’s Supernatural episode? — Tina
Not only does Rowena help the boys return to Apocalypse world, but she also develops an unexpected connection with the archangel Gabriel that surprises everyone
 
 
 
 
 
The sneak peek
 
 
Inside Supernatural
 
 
 The promotional pictures
 
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See the discussion thread for episode 21 for rumors, Behind the Scenes Pictures and more.
 
So the gang, Sam, Dean, Cas and Rowena, is going to try to kill Lucifer. It looks like they have to go through some monsters first. Gabriel is working with Sam, Dean and Cas and Rowena. Sam and Dean definitely end up in Apocalypse world and Gabriel and Rowena take on Lucifer. What do you think? Let us know in the comments or in the discussion thread for episode 21.