The Rook is based on O'Malley's genre novel which introduces a strong female protagonist named Myfanwy Thomas with extraordinary powers who is employed by a mysterious British government agency responsible for defending the UK from supernatural threats.
The show centers on a group of seemingly unconnected strangers who die from the energy pulse after a mysterious object crashes down to Earth. They awaken to learn that they have been deemed responsible for preventing the impending Apocalypse.