A project is underway that uses big data to clarify what happened to the more than 20,000 people who died or went missing in the Great East Japan Earthquake. Eleven participating companies, including Google, Twitter, and Honda, have offered their data for analysis. With private industry, government, and academia working together, new tools are also being developed to cope with future disasters. This documentary traces what motivated people to do what they did on the day of the earthquake, while showing how big data provides an understanding that goes beyond photographic and video images. Through the analysis of data collected from cell phones and car navigation systems (including 180 million tweets), the movements of tens of thousands of people are tracked, and the individual lives of those who faced this horrible disaster are brought into clearer focus.