In the "City of Lumen" shrouded in metal dust, memory is a commodity that can be extracted, traded and erased, and is circulated in the form of "Memory Crystals". Xunmo, a scavenger with incomplete memory, is looking for his deprived past among piles of discarded memory crystals. Lingyin, a top memory "washer", takes it as his life duty to remove "harmful memories" and maintains the false tranquility of the city. When a memory crystal carrying a forbidden lullaby entwines two unrelated destinies, they begin to unearth the secrets buried in the core of the city. This secret is not only related to their own identity, but also enough to subvert the order and existence of the entire Lumen City. On the ruins of truth and lies, they must choose whether to find themselves or to protect this world built by lies.
