Luke Rutherford (Christian Cooke) is just an average London teenager trying to live an ordinary life of going to school and parties. However, when his dead father’s best friend, Rupert Galvin (Philip Glenister) unexpectedly enters his life, Luke’s ordinary existence quickly turns extraordinary. Rupert is a demon hunter from America with a sarcastic sense of humour. But one thing Rupert takes seriously is convincing his godson, Luke, that he is the great-grandson of the legendary Abraham Van Helsing which subsequently puts Luke in charge of slaying the gathering dark forces.
With the assistance of Mina Harker, a blind concert pianist and authority on half-lives such as demons, vampires, zombies and werewolves, Rupert teaches Luke how to conquer the half-lives. Luke’s best friend, Ruby, joins the action and it’s not long before the four are walking the streets of London fighting the demons that lurk in the most unexpected places.
But a dangerous vampire, Gladiolu Thrip (Mackenzie Crook) has also discovered Luke’s secret. Does Gladiolu have enough power to prevent Luke from fulfilling his job of protecting London?