Uncover a land that has been hidden for over a thousand years. Beneath the land of Britain, a great army is sleeping. On a visit to an old church, Daniel Tully and Freya Reynolds awaken two ancient knights from a centuries-old slumber. They are kidnapped and taken to an underground city that stands in peril, besieged in all directions by a vicious warhost. Nidergeard is the only thing protecting the upper world's blissful ignorance of mythical forces that have been held at bay since the creation of the world. In order to return home, Daniel and Freya must strike at the heart of the opposer's power. Fast forward eight years. Daniel, now homeless, still wages what he believes to be a righteous war against those he judges to be evil. Freya has tried to put the past behind her and concentrate on getting an education, a job, and a life. When they reconnect in Oxford, unseen forces begin to ally against them. Daniel is pulled through a portal and into another world. Freya is abducted by someone—some thing—posing as her professor and drugged to keep her in a delusional state. After they finally break free, neither can deny the truth . . . they must return to Nidergeard and resume the battle. With a thrilling narrative that draws heavily upon British mythology, The Realms Thereunder will quickly establish Ross Lawhead as a major new voice in fantasy.

Ancient legend tells of an army of knights that will remain sleeping until the last days. The knights are waking up. A homeless man is stalked by a pale, wraithlike creature with a mouthful of needle-sharp teeth. Maimed animals and a host of suicides cluster around a mountain in Scotland. And deep beneath the cobbled streets of Oxford, a malicious hoard besieges a hidden city. Freya Reynolds is a university student with a touch of OCD and an obsession with myth and folklore. Daniel Tully is living rough on the streets of Oxford, waging a secret war against an enemy only he can identify. Years ago, they found themselves in a world few know is real. They have since gone their separate ways and tried to put that adventure behind them. But the mythical world is now bleeding into our reality—a dark spiritual evil that is manifesting itself in forgotten corners of the British Isles. Alex Simpson is a Scottish police officer who specializes in hunting mythical creatures. Together, they must confront the past, the present, and points beyond to defeat the ultimate threat to humanity. Nothing they've seen so far prepares them for what awaits . . . in The Realms Thereunder.

Daniel and Freya, along with an ancient knight and a Scottish police officer, must return to the underground city of Nidergeard in order to rally the citizens and stop the murder of sleeping knights.