The Winchesters must act fast in order to prevent another demon attack that could kill them and the other hunters in the next episode of "Supernatural" season 12.

According to the synopsis for the episode titled "Celebrating The Life of Asa Fox," Dean (Jensen Ackles), Sam (Jared Padalecki) and their mother, Mary (Samantha Smith), will join a group of hunters who will commemorate the life of one of their own who died tragically.

But as they mourn together the death of their fellow hunter, they will realize that a demon is bound to kill them one at a time. This means that the Winchesters must act fast to stop the demon's plan to obliterate the hunters.

Reports also revealed that "Pretty Little Liars" star Kara Royster will appear in the upcoming episode. She will reportedly portray the role of Alicia, a hunter raised by a witch together with her brother Max.

The episode will also see the return of Billie (Lisa Berry). The reaper was last seen in the finale of season 11, titled "Alpha and Omega," where she helped the Winchester brothers gather a huge crowd of souls that they can use as their weapon to destroy the Darkness. In the trailer for the upcoming episode, Billie will warn the hunters that "everyone dies" because of the demon.

Another returning character is Sioux Falls, South Dakota sheriff Jody Mills (Kim Rhodes). She will join the Winchesters as they pay their last respects for the hunter who died in the line of duty.

The Futon Critic revealed the synopsis for the upcoming episode, which reads: "When hunters gather together to celebrate the life and tragic death of one of their own, Sam, Dean and Mary must take action when a demon starts picking off hunters one by one."

The episode is slated to air on Thursday, Nov. 17, at 9 p.m. ET on The CW.