In a future where technology can turn forgotten memories into "memory crystals," Lin Mo is a "memory salvage man." He sailed through the "Sea of Forgotten" where all the forgotten things of mankind gathered, landed on the isolated island composed of memory fragments, and retrieved the lost past for his clients. Once, he accepted a commission from the business giant Chen Dong to find the last memory of his deceased wife - a "Sapphire Butterfly". However, when Lin Mo went deep into the forest of memory, he found that the wings of this butterfly were actually flapping the shadow of his blank past. He was forced to face a cruel truth: every salvage operation was a stripping away of his soul.
