Everything we know about Supernatural Season 13 Episode 20.
 
The official Press Release
 

“Unfinished Business” — (8:00-9:00 p.m. ET)

DIRECTED BY AND GUEST STARRING RICHARD SPEIGHT, JR – Gabriel (guest star Richard Speight, Jr.) is back and drags Sam (Jared Padalecki) and Dean (Jensen Ackles) into his plot for revenge on the demigods who sold him to Asmodeus. Meanwhile, Jack’s (Alexander Calvert) inflating confidence leads to reckless decisions that could put others in harm’s way. Richard Speight, Jr. directed the episode written by Meredith Glynn (#1320). Original airdate 4/26/2018.

Source:

The CW

 
 
 
The sneak peek
 
 
Inside Supernatural
 
 
 

Please tell me we haven’t seen the last of Gabriel on Supernatural!? — Ann
You definitely haven’t seen the last of Gabriel. This week’s episode not only features him prominently, but you’ll finally get some answers about how he ended up in Asmodeus’ possession — and those answers will actually lead to viewers finding out some information that dates all the way back to Gabriel’s first run on the series.

 
We have  interviews with Richard Speight, Jr. on his return as Gabriel
 
 
 
The promotional pictures
 
13.20_0025_kazoo.jpg13.20_0034_Gabriel_smiling.jpg13.20_0052_Bokken_.jpg13.20_0054_Animal_spirit.jpg13.20_0142_alley.jpg13.20_0151_gabriel.jpgSN1320a_0003b.jpegSN1320a_0026b.jpegSN1320a_0035b.jpegSN1320a_0037b.jpegSN1320a_0066b.jpegSN1320a_0086b.jpegSN1320a_0118b.jpegSN1320a_0167b.jpegSN1320a_0232b.jpegSN1320b_0064b.jpegSN1320b_0114b.jpegSN1320b_0155b.jpegSN1320b_0166b.jpegSN1320b_0232b.jpegSN1320b_0276b.jpegSN1320b_0306b.jpegSN1320b_0342b.jpegUB1.jpgUB2.jpgUB3.jpgUB4.jpgUB5.jpgUB6.jpgUB7.jpgUB8.jpgUB9.jpgUB10.jpg
 
From the writers of Supernatural
 
 
 
 
 
 
 For more information, rumors and Behind the Scenes photos check out the discussion thread for episode 20.
 
Gabriel wanting revenge makes a lot of sense, but he doesn't look in good shape. We go back to AU land as Jack and Mary try to kill Michael and AU Kevin shows up again. Sam and Dean hang out in a motel. Oh, Jack! Don't hurt other people! What do you think about this information? Let us know in the comments or in the discussion thread for episode 20.