The premise of the project centers around the possibility of a 7.0 earthquake hitting Tokyo with a 70% chance within the next three decades. In contrast, the anime depicts the devastating effects of an 8.0 earthquake. The lead character is Mirai, a first-year middle school student. While on summer vacation with her brother Yuuki, the pair visits the Odaiba Island to attend a robotics exhibition. Suddenly, a powerful quake shakes the city, causing the Tokyo Tower and Rainbow Bridge to crumble, bringing swift change to Tokyo's scenery. The siblings join forces with a female motorcyclist named Mari, whom they meet on Odaiba, and together they make their way back to their home in Setagaya, located to the west of Tokyo.