The exiled settler Alexander Ilyin persuades the gold mine owner Trifon Perfilyev to sponsor the expedition dedicated to the search for "Sannikov Land", a legendary warm land behind the polar circle. Hoping that this land could be filled with gold, Perfilyev agrees. A few more daredevils volunteer for the mission. The finally gathered crew consists of Ilyin himself, officer Evgeniy Krestovskiy, Perfilyev's servant Ignatiy, who is given a task of killing every other crew member in case they really find any gold, and Gubin, a Katorga runaway and a former doctor.
After a long journey, they reach the volcanic land and meet the natives – a tribe of "Onkilon". However they soon find out that the volcano is cooling down quickly, and the legendary land is about to start to freeze so that its unique ecosystem is doomed. Gubin chooses to stay with the Onkilons so as to share his knowledge and help them through the disaster, Ignatiy is killed, Krestovskiy falls from a cliff, and Ilyin has to return alone. Exhausted, he is picked up in the wilderness by Yakut hunters. As they carry him to safety, he watches the migrating birds overhead flying to the Sannikov Land, still unaware of its demise.
