An ordinary outdoor trekking activity for travel friends, a sudden heavy fog trapped several strangers in the mountains. While staying in a temporary shelter on the mountainside for the night, a large-scale landslide occurred without warning. Only programmer Lin Mo, female doctor Su Qing and Zhao Dajun, a self-proclaimed old travel friend, survived. During the desperate days of waiting for rescue, the thoughtful Lin Mo discovered some traces from the ruins that were not natural disasters. The collapse does not appear to be an accident. As the investigation deepens, distrust among the three begins to grow, and each person's reasons for being on the mountain become questionable. They realize that they may not be survivors, but selected prey. In the isolated mountains, the real danger is not the harsh natural environment, but the deadly truth hidden in the fog and people's hearts.
