We have the synopsis for Supernatural season 13 episode 20.
 
“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

 
Gabriel wanting revenge makes a lot of sense. Oh, Jack! Don't hurt other people! What do you think about this synopsis? Let us know in the comments or in the discussion thread for episode 20.