Lin Xiaoman, a social worker who works hard in the "Fog City", rents the second bedroom of his apartment to the mysterious tenant Shen Zhiyan in order to relieve the pressure on his mortgage. But since this tenant moved in, Lin Xiaoman's life has been completely "derailed" - not only does he frequently dream of ancient courtyards he has never been to, but he also always catches Shen Zhiyan crying in the air, and even finds an old photo of a woman who looks exactly like him in his wallet. As strange things such as "shared memory" and "time and space fragments" happened one after another, Lin Xiaoman learned that the "memory key" that Shen Zhiyan had been searching for for hundreds of years was actually hidden in him. The two redeemed each other in "solving the mysteries of the past life" and "dealing with the troubles of the current life", but they did not know that there was an even more outrageous truth behind it: their meeting was not a coincidence at all, but someone secretly changed the "life script" "backstage".
