Just as Charlie comes to terms with being born a Nephilim; an angel-human hybrid, the prince of Hell, who was once obsessed with her mother, has now set his sights on Charlie, and tries to convince her that he is her father. Thomas' absence leaves Charlie with no one to dispute Lucifer's claim, leaving her with no choice but to consider the unsettling possibility that her seraphim side may stem from a place of evil. 
  The same demon that attacked her before returns with a vengeance. This time, Ralph Knox intervenes and Charlie is shocked when she discovers he has been keeping a dark and terrible secret.
   As Charlie delves deeper into Alex's past, she learns she is not the only one who has suffered a heartbreaking loss.
   Alex is determined to get justice for a ghost from his past. If Charlie helps him, she may lose her heart, but if Alex is not careful, he's going to lose his soul.

 Betwixt & Between is the second book in the Seraphim Saga, following Burning.