There are two Earths. Our Earth is a place where magic and demons are things of folklore and legend. Dark Earth, is a dimension created in the high middle ages to exile Demons and other creatures, ushering in a new age. Man was left in peace, safe for the most part from the demon magic onslaught.
A mythical object known as the Tether remains hidden on this Earth. This object is the key to keeping both Earths separate and allows for a large passageway between both worlds when activated. The Tether had been lost for centuries, until Nacelle, a demon under-Lord tracked it down to a small Northern Town. In order to retrieve the coveted object, he opened Clean El mines employing half the town to dig for it, under the guise of mining for Nickel.
Nathan Mallstrom, a young local miner, finds himself in the middle of an ancient battle between the Earths as he stumbles onto the Tether during one of his shifts.
This is a classic hero's story. The young Nathan is caught in the imminent battle for the Earth. Summer Vale, a super soldier with demon DNA is there to guide him in the battle. With Nathan's sister Gwen and Summer's side kick Bulo, they try to unlock the mystery of the Tether and fight to protect the world from Nacelle and the Demon Lords who want to rule it.