Set in  an  alternate 1950's America, witches, demons, and magic  are real. Oliver, a bitter incubus, is accidentally summoned by Ava, a very forgetful witch, as her Familiar. Together, they must  explore the far reaches of the world to  obtain rare  components to  complete the ritual that would break their bond, setting Oliver free.

 

However, their  adventure doesn't  come without  a price. A group known  as the Harvesters are hunting witches like Ava down, and their leader seems to have taken  an interest in the pair. Oliver  and Ava must learn to work together while  avoiding the Harvesters at  all  costs to see their journey through to the  end.