Dissatisfied with the lackadaisical life she’s been living up to now, Mari Tamaki decides to skip school and venture out into the unknown, but is too scared to eventually go through with it. One evening, she comes across an envelope dropped by a girl, and discovers it contains one million yen. She soon learns that the girl, Shirase Kobuchizawa, has been saving up the money to travel to Antarctica and find her missing mother.