Memento Mori

It is about a girl named Leda Summers who was adopted after being given up by her mother who, she was told, was a drug addict. As Leda gets older, things get odder. Were those ghosts she just saw? And why did her mother send her a distressing phone call after not talking to her for four years? And who was Case Ford? As Leda tries to unravel these mysteries and learns the truth, she discovers something frightening about herself.