A comet appears and mysteriously affects and connects the lives of two teenagers of the same age, a boy in the big, bustling city of Tokyo and a girl in a country village where life is slow but idyllic. They find for unknown reasons, they wake up in each other's bodies for weeks at a time. At first, they both think these experiences are just vivid dreams, but when the reality of their situations sinks in, they learn to adjust and even enjoy it. Soon they start to communicate and try to leave notes about who they are and what they are doing. But as they discover more about each other and the other's life, they uncover some disturbing hints that their distance is more than just physical and tragedy haunts them.