The story revolves around a computing major named Li Yuchen who is adept at solving problems using probability. He is extremely intelligent, kind-hearted and helpful but he comes off a bit uncaring and cold. He meets Xia Xiaoci, a cheerful girl from an ordinary family and they start out with an immediate dislike for each other.

Do Over follows five characters over twenty four hours on the last day of the year. As the interrelated stories proceed, the connections between the lives of the five characters begin to reveal themselves and their stories unravel. By depicting five different characters at emotional crossroads, Do Over examines the struggle of overcoming our greatest fears; the unknown of what lies ahead in the future, the fading value of our existence in the present, and most of all, irreversible mistakes made in the past that may catch up to us.