Dean (Jensen Ackles) loses his memory after he gets hit by a spell in “Supernatural” Season 12, episode 11. Pictured: Ruth Connell as witch Rowena and Ackles. Dean Buscher/The CW

“Supernatural” is taking a page from “Memento” in its upcoming episode on The CW. After Castiel’s (Misha Collins) past was revealed last week, this week the focus shifts to Dean Winchester (Jensen Ackles).

In Season 12, episode 11, Dean will get hit by a powerful spell that will rapidly erase his memory. At first it seems fun and the hunter forgets all his struggles and baggage from years of hunting supernatural creatures like witches, vampires, ghosts and ghouls. It feels freeing in a way. The eldest Winchester will be trapped in a “Memento”-like loop. As we reported earlier, Ackles’ character becomes more fun and childlike.

The promo shows Dean blacking out and losing track of what he did the previous night. Rowena (Ruth Connell) likes this version of him. She asks his younger brother Sam (Jared Padalecki), “Do we have to fix him?”

Of course Sam and Rowena will have to fix him because soon he starts to forget his younger brother. Shortly after forgetting his brother, he starts forgetting who he is.

Together, Sam and Rowena track down a powerful family of witches from the old world. Only they can help Dean remember his past. It will be nice to see Rowena back in action this week.

Castiel is visibly absent from the preview. His angelic past was heavily featured in episode 10. “Supernatural” fans discovered that the angel has come a long way from despising humans to being extremely loyal to the hunters.

However, the fact remains that Cas killed Billie the Reaper in order to save Dean’s life. She warned them that if they did not fulfill their end of the bargain that there would be cosmic consequences. When will the angel have to pay up for his action? Only time will tell.

Catch “Supernatural” Season 12, episode 11 on Thursday, Feb. 9 at 8 p.m. EST on The CW.