In a small town, twelve mysterious letters and a 35-year wait intertwine to shape the lives and loves of a close-knit group of friends. Yu Nian and Shen Cheng’s world is thrown into turmoil when their parents vanish, followed by cryptic messages arriving from another time. Driven to uncover the truth, they plunge into a complex puzzle, navigating dual timelines and unraveling the secrets hidden within the letters that could explain their disappearance.