When the gray fog descends, the city loses its former order. After living alone for three months, Huo Wei unexpectedly discovers a "Time Reversal App" on his phone, which allows him to connect to the internet from three years in the past for ten minutes each day. To help everyone, he begins posting warnings and sharing his observations and survival tips. At first, nobody believes him, until a message from the past brings a new clue. The once-silent world gradually begins to show signs of other survivors. Following these clues, Huo Wei embarks on a journey to find companions.