I cant remember the title as it was such a long time ago, but a certain book I read as teenager made me realize that I have a flipside to my soul. It was a horror novel about a young German woman's search for her missing sister in Europe. The police are of no help, they just want bribes, so she has to pick up the trail in Bavaria where her sister last made contact. Going from town to town she gradually ends by a process of elimination in the foothills of the Berchtesgaden Alps, where she picks up a lead, not in words but of hand gestures.

The villagers will not answer a single question about missing persons, but would only point with their finger into the Mountains where an ancient convent of nuns was established in the Middle ages. So of course, she arranges to visit this place and interview the Abbess. Everything seems fine there for a few days, the sisters are reserved but welcoming and claim to have no knowledge of anything useful. However, there are a few strange details. The Abbess is found to occaisionally reveal a glimpse of black high heels under her thick woolen habit. And the nuns under her leadership have tiny tattoos inked on their ankles...some arcane symbol that is definitely NOT Christian. On her last night there, she happens to catch a glimpse in the dark hallways of a young nun dancing with the shadow of a goat...dancing on its hind legs!!!

Thats one hell of a bad sign! Confused and intrigued, she leaves and makes her way down the mountainside where she meets an old man searching for medicinal mushrooms. He is far more communicative than the villagers and tells her that all is not right and holy among the nuns.

"Their souls have fallen backwards into hell" he whispers in hushed tones. 

With some persuasion, he further reveals that many years ago a demon appeared to the Abbess in the dead of night and told her that God was displeased with her and she could not be redeemed. The demon offered an alternative...one that would embrace every desire of the flesh and secure a high place among the souls consigned to the chasm of fire. 

The old man leads her to a narrow fissure in the mountain's rocky face...a secret tunnel.

'Leading where?" she asks.

"The passage leads down into the caverns under the convent...take the deep path and gaze into the abyss. There you will find your answer."