On a moonlit island, residents begin seeing luminous white figures that seemingly pass through solid matter; a frightened servant leads two friends and a young woman to investigate and they encounter further inexplicable apparitions. Skepticism yields to alarm as the phenomena escalate and are revealed to originate from a fourth-dimensional realm whose materialized inhabitants possess formidable, apparently invincible power. The story combines eerie atmosphere and investigative pacing with speculative ideas about higher dimensions and an otherworldly invasion that forces ordinary people to confront an extraordinary threat.