HBO to Produce 'Game of Thrones' Prequel 'House of the Dragon'.br According to the network, 10 episodes have been ordered for the spin-off.br It will be based off the George R.R. Martin's book, 'Fire & Blood.'.br The 'GoT' author released the first volume of 'Blood' in November 2018.br 'House of the Dragon' will center on the br Targaryen family, Westeros' previous rulers br before the events in the show.br The prequel is set 300 years before everything set in motion from br the first 'GoT' book.br Miguel Sapochnik, who has directed br six 'GoT' episodes, has signed on to helm the pilot.br News of the program's confirmation comes after HBO cancelled another 'Game of Thrones' spinoff.