The film was inspired by a real dog which was featured in a segment called "Kyou no Wanko" (today's doggie) on the Fuji TV morning program "Mezamashi TV".
Based on a true story, the film centers around a family consisting of father Matsuo (Sato Ryota), mother Takako (Aso Kumiko), grandmother Fusako (Baisho Mitsuko), and son Shin (Hashino Ryunosuke) who live together happily at the bed and breakfast they run on Miyakejima.
However, in August of 2000, the residents of Miyakejima are forced to evacuate the island immediately due to a volcanic eruption and Shin must abandon his dog, Rock, whom he had grown up with since birth.
Following the evacuation, the family is confronted with various problems such as getting used to living in an unfamiliar city. But through it all, Shin refuses to give up hope of being reunited with Rock someday.