In the future urban "Floating City" where memories can be extracted, stored and traded, Lin Mo, a top memory restorer, spends his days sneaking into the sea of other people's broken memories, repairing emotional rifts, but he is unable to retrieve his own key memory of the day his sister disappeared. A mysterious commission draws him into the center of the whirlpool: a woman named "One" asks him to repair a memory that has been marked as taboo by the "gravekeeper". When Lin Mo sneaked into the dangerous ruins of memory, he discovered that the lost key could not only unlock the client's secrets, but also point to his own dusty past, as well as the cruel truth about "eternal life" and "forgetfulness" beneath the city's glamorous appearance.
