The Abyssal Engine

From publisher blurb: A famous explorer discovered a grotto cave near the mountains. Recent heavy rains and storms revealed a hidden tunnel after a small section of the mountainside collapsed. Since that day, Frederic Denney has become obsessed with his findings. However, this ancient cavern holds a dire secret he is not aware of. He does not sleep anymore and he spends his days writing and mumbling in tongues he did not know before. The obscure influence of the place has corrupted the explorer. It is just a matter of time for Frederic to fall deeper into darkness and perform a ritual that shall free an evil entity from its prison.