A strange bloody mist enveloped the earth. Seven survivors with different identities woke up in the ruins. Metal rings with numbers engraved on their wrists appeared at the same time - starting from 7 and decreasing by 1 every day.
They soon discovered that this area known as "ash soil" was decaying at a speed visible to the naked eye: on the first day, the drinking water began to smell of rust; on the second day, all electronic equipment collectively failed; on the third day, inhuman chewing sounds were heard at night... And the number zeroer of the metal ring would mysteriously disappear at midnight, leaving only a pool of burned black ash.
Former soldier Lao Gu held a rusty dagger and tried to use his tactical knowledge to find a way out, but found on the fourth day that they were always circling the same abandoned hospital; the female student Lin Xiaoman could understand the whispers coming from the ashes, and those broken syllables pieced together a name that was exactly the same as her missing sister; the man wearing a priest's badge always stared at the metal ring while praying, and no one knew that half of a blood-stained map was hidden in his pocket.
When the number jumped to "3", someone found a diary in the basement of the hospital. The last page was written in blood: "At the dawn of the seventh day, those who survive will become the new key." At this time, the survivors finally realized that the metal rings on each other's wrists were exactly the floor plan of the hospital, and the rules of the next round of the game were hidden in the black ashes left by the disappeared ones.
Deep in the mist, huge gears are turning. What they thought was a race for survival might just be the prelude to an ancient ritual, and the so-called "embers" might have been burned repeatedly in countless reincarnations.
