The story takes place 26 years after the outbreak of the nuclear war in 1986. In 2012, an immersive play “We Won’t Grow Old Together” opened up at the comet theater. At the end of the play, actress Fang Fei, who played as the piano teacher Oliveira, disappeared from the theater stage. This case became an unsolved mystery case with the day after day futile investigation. A year later, the theater’s owner, Takahashi, enlisted a Japanese-Brazilian actress named Nakajima to recreate the tragic fate of piano genius Oliveira Marquez. At the same time, Fang Fei’s mother, Yang Fuzhi, received an anonymous letter indicating that her daughter still seemed to be living somewhere in the world. Yang Fuzhi found the city’s most outstanding private detective – “Y” to investigate the whereabouts of her daughter. “Y” enters the comet theater and follows the crowd into the family tragedy and gradually sinks deeper into the mystery. Everyone seems to be lying and listening to their own voices. Surprisingly, the comet theatre was the Big Bright Rink 26 years ago, where Y’s father was drawing an advertising oil painting for the owner. An underground maze was found by “Y” and owner’s son, Lin. Lin appeared in the audience at the night of the performance in 2012, and got into the entrance of the maze with Fang Fei, disappeared forever in the dark underground world.