The synopsis for Supernatural season 13 episode 9 the mid-season finale.
The Bad Place” — (8:00-9:00 p.m. ET) (Content Rating TBD) (HDTV)

JACK AND KAIA DISRUPT THE WORLD – Jack (Alexander Calvert), desperate to prove to Sam (Jared Padalecki) and Dean (Jensen Ackles) that he is good and that he can control his powers, enlists the help of a dreamcatcher named Kaia (guest star Yadira Guevara-Prip) to help him find Mary Winchester (guest star Samantha Smith) and save her from the alternate universe. However, when plans go awry, the Winchester brothers are the ones who need saving. Phil Sgriccia directed the episode written by Robert Berens (#1309). Original airdate 12/7/2017.
Jack is back and trying to prove he is good, by finding Mary. What do you think goes wrong that puts Sam and Dean in danger? Will Jack get Mary out of the AU? What role will this dreamcatcher play? Tell us in the comments or in the discussion thread for episode 9.