Alleghgella is a bundle of stories, poems, and incantations passed from a recluse named River to his long-lost friend during a chance encounter in the woods of their shared childhood. The friend is tasked with preserving this collection by publishing this book. River had disappeared for decades, and the origins of this eclectic collection remain unclear. Some pieces are told by voices from beyond the grave. Still, it draws on personal experiences, oral histories, myths, and small-town lore, set across various periods spanning hundreds of years-most relating to a specific stretch of land and towns along the Allegheny River in Western Pennsylvania.

Various pieces seem to be seasoned with Grateful Dead lyrics.