Lin Zhixia, an urban white-collar worker, accidentally dug up a "youth time capsule" buried with her friends ten years ago during the anniversary of her high school alma mater. The capsule should have been a childish note of wishes, but instead there was an unsigned letter - the letter contained a secret that only she and her late friend knew, and also hinted that her friend's "accident" that year was no accident.
From then on, Lin Zhixia's peaceful daily life was broken: strange traces appeared frequently in her home, anonymous warning text messages were received on her mobile phone, and her classmates from ten years ago looked away when they mentioned the past. While pretending to work and live as usual, she secretly pursued clues. She pieced together the hidden truth bit by bit in urban office buildings, old neighborhoods, and class reunions, and gradually discovered that what was hidden in the time capsule was a fatal mystery that entangled her youth.
