Deze serie volgt een gewone politieagent uit Oxford die onverwachts wordt meegesleept in een geheime oorlog tegen angstaanjagende interdimensionale wezens. Ondanks zijn aarzeling en zijn zelfverklaarde gebrek aan heldendom, moet hij de realiteit bedreigende, de waanzin tartende kosmische verschrikkingen trotseren. Het verhaal combineert urban fantasy, actievolle thriller-elementen en kosmische horror, en verkent thema's als moed en de grenzen van menselijk uithoudingsvermogen. Het biedt een meeslepende reis van een gewone man die buitengewone bedreigingen onder ogen ziet.
Oxford police detective Arthur Wallace is a good cop, but prefers that action and heroics remain on the screen, safely performed by professionals. But then secretive government agency MI12 comes calling, hoping to recruit Arthur in their struggle against the tentacled horrors from another dimension known as the Progeny.
Another day, another zombie T-Rex to put down. All part of the routine for Arthur Wallace and MI37 - the government department devoted to defending Britain from threats magical, supernatural, extraterrestrial, and generally odd. But a zombie T-Rex is only the first of Arthur's problems, as Russian cyborg wizards threaten his life...
When MI317 - the government department devoted to defending Britain from cosmic horrors and otherwordly threats - comes under attack, Arthur Wallace and his team begin a race from Area 51 to an Arctic town populated entirely by spore zombies to save the world and halt the destruction of humanity.
Arthur Wallace and the MI37 team confront their personal relationships as well as robots created to aid the Nazi's invasion of Russia, leading to a trip for the team to the Himalayas, which takes them to a Nepalese death cult, then back to London for the final assault - amidst assorted relationship break-ups, hangovers and pregnancy scares.