Tokyo Magnitude 8.0 is set against the backdrop of a 70 % chance that a magnitude‑7.0 earthquake will strike Tokyo within the next thirty years, and it explores the consequences of an 8.0 quake. The story follows Mirai, a middle‑school freshman, who travels with her brother Yuuki to Tokyo’s artificial Odaiba Island for a robot exhibition at the start of summer vacation. A powerful tremor originating from an ocean trench causes the Tokyo Tower and the Rainbow Bridge to collapse, instantly reshaping the city’s landscape. With the help of Mari, a motorcycle deliverywoman they meet on Odaiba, Mirai and Yuuki set out to return to their home in Setagaya, western Tokyo.