In Kyushu, southwest Japan, one hot summer morning, a municipal bus is hijacked. In the carnage, only three people survive: the driver, a schoolgirl, and her older brother. Suffering from trauma, the driver disappears. The children withdraw in silence. Two years later, their mother has divorced and their father dies at the wheel of his car. They now live alone in the family home. The driver returns to town and takes up household with the children, who are soon joined by their cousin, a college student on vacation. When the body of a murdered woman is discovered on the riverbank, the police suspect the driver. Soon after, he buys an old bus, fits it with beds, and invites the three young people to leave on a trip.