Gu Chen traveled to this different world and was inexplicably invited to an isolated island villa. Seven guests received anonymous letters one after another, and then someone died mysteriously in the secret room. The body was in a strange posture, and a non-existent figure appeared in the surveillance. As a time traveler who is familiar with Cthulhu culture, although Gu Chen has the advantage of being a prophet, the investigation is difficult in the face of the suspicion and fear of other survivors, as well as the constant loss of sanity. As the death toll increases and time becomes increasingly urgent, he also needs to hide his identity as a time traveler to prevent attracting more terrifying entities. In the end, Gu Chen uncovered the truth, only to find that all the deceased were fragments of "her" personality, and he himself paid a heavy price.
