Xia Xia is a single mother and a senior researcher at the Institute of Physics. For many years, she has been dedicated to researching particle technology that can go back to the past. On the day when Baobao's research is about to succeed, Xia Xia discovers that her son Doudou has been kidnapped by the mysterious kidnapper Cui Hu. Cui Hu threatens Doudou's life to hand over particle technology in the summer. In order to save Doudou's life, Xia Xia ventured back using unfinished particle technology 1 hour and 50 minutes ago, making things even more complicated. The story behind Cui Hu's story gradually surfaced.