Two friends take a fishing vacation in a remote part of Ireland, and they stumble across the crumbling ruins of a stone house which has been overtaken by the foliage of a long untended garden. The house sits at the edge of a deep chasm into which flows a river of subterranean origin and also, as we soon find out, acts as a door to another dimension.
Within the rubble, the two men find the journal of an old man who once lived in the house, and they take the journal back to their campsite for further perusal. The tale that resides inside of that age-worn book is a masterpiece of the weird.
Imagine watching billions of years pass before your eyes in a matter of days, and you'll get the vaguest sense of the apocalyptic imagery that exists within this book. It's both haunting and surreal, and the story even features a chilling cameo by that darling of India, Kali the destroyer.
The only thing that I didn't care for is the inclusion of the ethereal love interest, and that's mostly because it was terribly underdeveloped. The reader gets a better sense of the relationship between the main character and the dog, Pepper (who I really liked). Had Hodgson left the romance bit out, this book would have been nearly perfect.
An online version of the text can be found at Project Gutenberg.