In Atoll City, memories are commodities that can be retrieved, stored and traded. The city is surrounded by the "Sea of Oblivion", and that sea of fog will mercilessly erode people's memories. Xun, the top memory restorer, makes a living by repairing broken memories, but his heart is trapped by a blank past that cannot be repaired. One day, a mysterious woman named "Zero" brought a fragmented memory crystal carrying a murder scene and asked him to find the victim in the scene. In the process of searching for the truth, Xun found that the clues of this crystal pointed to his forgotten past, and his and Zero's fate had long been tied up in a huge conspiracy and sunk into the deepest part of the Sea of Forgotten.
