Shen Yubai lives outside the circle of close friends of the four of them. He is sensitive and reserved, and is used to burying his thoughts deep in his heart. When he was young, he wrote letters full of emotions, but never dared to send them out. He didn't want to join in the bustle, kept to himself, and remained alienated from his old friends. His hot feelings were sealed away by the years and became a regret that no one knows.
Lu Zhiheng is the gentle member of the foursome. He treats others with humility and sincerity, but he is bound by reality and cannot help himself. He knew Shen Yubai's thoughts and wanted to get closer, but many obstacles made him stop. Underneath the gentleness was the sadness of being unable to change the past.
Pei Shuo has a cold and taciturn personality, is straightforward and neat in his work, and values love and justice. He has the habit of taking responsibility alone when encountering problems and is not good at comforting others with words. He had seen through Lu Zhiheng's struggles and had seen Shen Yubai's loneliness. He never intervened forcefully and only used silence to protect his close friends.
Jiang Xu is transparent and keen, good at understanding the emotions of others, and always wants to resolve the knots between friends. But the young man's regrets are inexplicable. He can clearly see everyone's obsessions, but he can't bridge the gap, and he never tells anyone what's on his mind.
Shen Wangjin is gentle and quiet, accustomed to being a bystander, and never gets involved in the disputes between friends. He silently witnessed everyone's emotional ups and downs, silently accompanied others when they were depressed, quietly looked at the unfulfilled youth, and guarded the dusty past.
The four of them were together day and night, while Shen Yubai stood alone outside his memories. The unsent letters revealed the unspeakable youthful regrets hidden in the hearts of the young people.
Intention: The old envelope is kept, and the estrangement between the young people arises naturally, waiting for reconciliation in the future.