The story of House Targaryen will be told. House of the Dragon, the prequel to Game of Thrones, was announced by Casey Bloys, president of HBO Programming, at WarnerMedia Day. Here's what we know so far. What's it about: Based on George R.R. Martin's Fire & Blood, the series will tell the story of House Targaryen and take place 300 years before the events of Game of Thrones.