HBO is working hard behind-the-scenes to keep that sweet, sweet Game of Thrones train running well after David Benioff and D.B. Weiss‘ main series comes to an end. We’re currently up to five spin-offs in development, but the only one with concrete details and a timeline is the still-untitled prequel pilot written by showrunner Jane Goldman (Kingsman: The Secret Service) and directed by SJ Clarkson (Jessica Jones) with Naomi Watts leading the cast. The latest, according to HBO Programming President Casey Bloys [via EW], is that the pilot will begin production in early summer 2019, and if it’s greenlit (lol) the series could be on the air in 2020 or 2021.

The show, set thousands of years before Game of Thrones, will introduce audiences to a very different-looking world than the Westeros we know and love. George R.R. Martin, who has a story credit on the prequel, kickstarted the rumor that the series is titled The Long Night—named after a decades-long winter that birthed a war between the human race and the White Walkers—but that isn’t official quite yet. HBO has released a description, which promises plenty of violent frosty nonsense.

“Taking place thousands of years before the events of Game of Thrones, the series chronicles the world’s descent from the golden Age of Heroes into its darkest hour. And only one thing is for sure: from the horrifying secrets of Westeros’s history to the true origin of the white walkers, the mysteries of the East to the Starks of legend… it’s not the story we think we know.”

For more on the Game of Thrones prequel, click through the links below: