Courier Lin Yuan received the last order on a rainy night, but unexpectedly took over the strange envelope from the old man's hand, and has since become the mysterious postman connecting the abyss and reality. He travels through the fragments of time and space, delivering letters for obsessions that cannot be let go - from missing children to decades of waiting, each letter is a forgotten story. And the mystery left by his missing father for many years gradually emerged on the postman's journey. When Lin Yuan discovers the truth about the post office and "their" gaze, how far can he go when faced with the choice between the abyss and the world, rules and costs? Under the abyss, there is always a reply.
