Kelly Addams 
Styx [EPUB ebook] 

A freak accident has brought brat Lisa to the River Styx, the legendary boundary between the land of the living and the mythological Underworld. She is trapped, but there may be a way for her to return to the light if she successfully complete a series of tests. Lisa is going to learn a great deal about herself as she faces her personal demons, and admits who and what she really is.

Caution: This story features scenes of sadism, and sex with mythological creatures – Reader Discretion is Advised – 18+