Complex sentence: Interested in folklore, the narrator locates an elderly local drunk known for his tall tales, and is told of how seafaring inhabitants of Innsmouth generations before voyaged to the South Seas where they found a cult that practiced human sacrifice to placate immortal undersea creatures.
Split into simpler sentences: Interested in folklore, the narrator locates an elderly local drunk known for his tales. He hears that seafaring inhabitants of Innsmouth generations before had voyaged to the South Seas, finding a cult that practiced human sacrifice to placate immortal undersea creatures.