In New Ark City, memory is both currency and the deadliest weapon. The "Great Silence" seventy years ago erased digital civilization, and the human mind became the last archive.
Ling Yan, a promising memory architect, is now a notorious "echo hunter" in Xiacheng District. He sneaks into other people's broken memories and hunts down dangerous "echoes" that can drive the host crazy, just in exchange for the expensive medicine that keeps his sister alive. His world is intertwined with other people's past and his own regrets.
A commission from uptown broke his decadent daily life - the only son of the founder of Hippocampus Company disappeared mysteriously, and the only clue was hidden in the chaotic memory of his lover. Ling Yan originally thought that this was just a well-paid sneak, but in the abyss of memory, he came across a "corrosive echo" that should not exist. This echo is as powerful as a ghost, not only pointing to a taboo experiment that was covered up, but also secretly connected to the truth that his sister fell into a deep sleep.
When the boundary between reality and memory begins to dissolve, Ling Yan must uncover the manipulator hiding behind countless memories before his mind is completely swallowed up. What he has to face is not only the dark core of the city, but also the own abyss that he has been trying to bury.
