A man accepts an invitation from his best friend - Crawford Tillinghast - after a rift in their friendship regarding Crawford's scientific and metaphysical research, to discover Tillinghast has created a device that awakens sensory abilities long dormant in humans after millions, perhaps billions, of years of evolution, allowing us to see and experience all the worlds around us, previously separated from us by our five senses, and he further discovers that Crawford's invitation has an ulterior motive - revenge.
I could hardly understand anything being said for most of the second half of the book because of all the utterly over-the-top sound/voice effects. "Sonic movie," more like audio assault. I recommend looking for another recording, or just reading this one.
The story was great, but this was really frustrating to listen to.