After producing Chernobyl and Game of Thrones season 8, HBO has finally started the production of the first prequel series of Game of Thrones. The awaited TV series is going to feature Westeros and there are chances that we might get to see the birth and life of Night's Watch commander who would later become Night King.
Even before Game of Thrones season 8 aired, the network announced that it has been working on a couple of spinoff content featuring Westeros. It was revealed in 2017 that the network has reportedly hired five writers to pen five different Game of Thrones spinoff. As of now, only one from Jane Goldman has been given a pilot order by HBO.
As per the latest reports, Game of Thrones prequel series has already begun filing in Northern Ireland. The same place reportedly served as the main shooting location for Game of Thrones.
As we earlier stated, the upcoming Game of Thrones prequel series is set thousands of years before the events of Game of Thrones. In previous reports, it was made clear that the show will not feature any Royal Houses like Targaryen, Stark, Lannister, or Baratheon, as it will bring the story of world's descent from the Golden Age of Heroes to the rise of White Walkers.
It simply means that the upcoming untitled prequel series is going to feature how and why the Children of Forest converted a man from the Night's Watch to a White Walker. In George RR Martin's acclaimed books and the adapted TV show, we saw how Children of Forest kidnapped a man and stabbed a dragonglass into his heart and made him a White Walker. So, as per several theories, we might get to see the man behind Night King and his actions that will lead him to the Children of Forest.
Meanwhile, in one of his previous interviews, Martin talked about The Long Night and stated that there will be no Iron Throne as "Valyria has hardly begun to rise yet with its dragons and the great empire that it built."
Game of Thrones prequel series, The Long Night, may debut somewhere around April 2020 or 2021.