A butterfly in the Amazon rainforest in South America, flapping its wings occasionally, can cause a tornado in Texas two weeks later. When meteorologist Lorenz proposed the theory of the butterfly effect in 1963, Xia Lei, Xue'er and Xiao Ran were not yet born.
Forty years later, when Xia Lei learned about this theory, he felt a mixture of ups and downs in his heart.
An arrogant and willful act when he was young changed his life in this way.
If life could start all over again............