In the deepest part of the sand sea, Sujia walked alone among the quicksand and afterimages, looking for the unknown phantom castle - according to legend, only those who have been completely forgotten by the world can step into its door. Sujia voluntarily erased his own existence just to find his mother's lost name. However, every stone brick in the castle swallows up the memory of the visitor, and truth and lies intertwine and flow in the hourglass of the law of forgetfulness. Sujia struggled on the edge of losing himself, trying to piece together his mother's past with the remaining memories, but gradually discovered that the real phantom is the pain deep in the heart that does not want to be remembered. In the cycle of forgetfulness and pursuit, Sujia must choose whether to become a shadow that disappears completely, or to reveal the mystery of the fate behind the castle with amnesia - and does the world outside the castle still remember the traveler named Sujia?
