Psychological profiler Feng Wan received a yellowed anonymous letter, inviting her to go to an "Echoing Island" that did not exist on the map to investigate a bizarre incident. After landing on the island, she met up with eleven other invitees with different identities, but was horrified to find that of the twelve people listed on the invitation, only eleven corpses with different forms of death were found. Ancient stone statues turn their heads to stare at the living at midnight, and blood words appear out of thin air on the beach every day, accurately revealing the deepest sins in everyone's heart - including the memory of her sister's disappearance that was forcibly sealed by Feng Wan when she was seven years old. When the survivors discovered that all electronic devices were locked on the same series of ever-dwindling countdowns, the accompanying psychologist tremblingly revealed that: beneath their feet was not an ordinary island, but a mysterious altar where twelve young people committed collective suicide thirty years ago. Now, the survivors are showing symptoms of petrification one by one. Feng Wan must race against time to solve a double mystery that spans thirty years before she is completely turned into a stone statue: Why were there only eleven remains left in the suicide that year, but the name of a survivor was engraved on the twelfth one? And now, who is the "twelfth person" hidden among the survivors, who knows everything and controls the "trial"? Every intervention that attempts to change the past or present triggers new "echoes"—more terrifying visions and deeper doubts. The only thing Feng Wan can rely on is her unexpected ability to have a brief "conscious echo" with a key figure at the altar thirty years ago. But this ability is like a double-edged sword, allowing her to glimpse fragments of the truth while also facing the fact that she does not want to admit it.
