Returning to its home port, the Soviet icebreaker Mikhail Gromov collides with an iceberg that suddenly began to move and finds itself captive in ice off the coast of Antarctica. One of the polar explorers dies before the eyes of the crew, the ship receives serious damage, a block of ice threatens to completely crush the icebreaker... At the height of events, an order is received from the shipping company to remove the captain from leading the crew. People's nerves are on edge. Who will come to the aid of “Mikhail Gromov” if for hundreds of miles around there is only ominous silence and bitter cold?..