HBO has pulled the trigger on one of the reported Game of Thrones prequel series, and it looks like the show will be dark and full of terrors.

According to the network, the Game of Thrones prequel will reach back into distant history to chronicle “the world’s descent from the golden Age of Heroes into its darkest hour.”

And if you thought that Game of Thrones told you all of the dark details you needed to know, think again. “Only one thing is for sure,” HBO says, “From the horrifying secrets of Westeros’ 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.”

The Age of Heroes is the legendary time that followed the end of conflict between the Children of the Forest and the First Men of Westeros. A period of great deeds and great men, like Bran the Builder, Symeon Star-Eyes, and Lann the Clever, the Age of Heroes only came to an end with the Long Night, which still reverberates in the mysteries of Game of Thrones today.

The new Game of Thrones prequel series comes from Jane Goldman, the writer behind X-Men: First Class, and A Song of Ice and Fire author George R. R. Martin. Goldman will serve as showrunner and Martin will be an executive producer on the project.

Goldman’s Game of Thrones prequel is only one of five Thrones-rated projects commissioned by HBO as the radically popular series comes to an end. Though fans are sure to be hungry for details, it’s heartening to note that at least a part of the Game of Thrones world will be entrusted to a female creator, a unique development in the series’ history.