Lay, an ordinary and conservative engineer, fell in love with don, a veteran in love, because of a sudden encounter. He even boldly broke through and decided to live together. However, huge differences in concepts and unequal love caused the two to drift apart. When the struggle was coming to an end or beginning, a man named Liang broke into Lay's field of vision, and used gentleness and tolerance to help him find himself. He never wanted to donate but was unwilling to let go. How are the three people's emotions connected in the end?