Ember Reign is a novel series about a girl who sets out to solve the mystery of her grandfather's death. He and his father were part time archeologists who discovered certain mysterious devices in their travels and brought them home. Megan and her friend find these devices while trying to solve the mystery as well as save grandmother's farm.
More mysterious than the artifacts are their creators, ascended beings having God like powers. They have watched over humanity for countless ages and were known by several names. The girls call them "The Great Old Ones."
Their craft is alive, larger than a football stadium outside and many times larger inside. Filled with living specimens in suspended animation Orion is a kind of Ark.
The girls take command of Orion and discover they are the main thing standing between humanity and a full scale alien/demon invasion.
Each more intense than the previous revealing more of the mystery.