Mikura Amelia runs an air delivery service with her grandfather in Izu Ōshima, Japan. After finding out that he has died, she discovers his journals about "Electric Island" left for her and a package for her to deliver there. The entries are written into the future and provide Mikura with instructions on how to locate the island, which doesn't have a fixed location. After three days, she manages to find the island using wave radar, but upon going in for a landing, falling debris from a burning building causes her to crash. Mikura is rescued, but the island is gone. Mikura resolves to find Electric Island again, neglecting her sleep and deliveries to the point of losing electricity in her house. Based on the journals, she learns that the island moves around cyclically over a period of approximately three years. She also receives the notes of Ryugo, her former teacher and a geophysicist w