The narrator, "Yu Shuhan," has been studying in the United States since high school. She met all kinds of people outside and saw fireworks that were different from those in Beijing. She once looked forward to a different youth, but later she discovered that everyone's stories were surprisingly similar. When she went through the long years of studying abroad, she wanted to leave some words as evidence that she had been here and loved her. Also hide in the years the people who struggled to be retained in my memory.