Ether.

At the end of the 19th century, somewhere in the outskirts of the Russian Empire, a doctor administers a lethal overdose of ether to a young woman – the object of his desire. After getting away with his crime, he finds employment in a fortress, where he continues his experiments with ether to manage pain and manipulate human behaviour. Despite his evilness, it is not too late for his soul to be saved from eternal damnation…