Letter to Anna

In 2197, 122 years after the nuclear winter and 22 years after humans left the underground shelter, human science and technology development reached a new peak under the theme of reshaping the human world. The development of nanotechnology and the application of dark matter fuel ignited the flame of curiosity in people's hearts, so people began to study the most elusive dream of mankind - traveling through time and space. But just when people were conducting manned experiments on the "time machine" for the first time, an accident happened...