An avalanche cuts off builders of the Baikal-Amur railway from civilisation. Alexander Ivanov's team tries to find a short way through the Taiga to progress the railway.

The men stole a barrel from the basement of the main depot of table wines, but failed to deliver it home. They did not hold the barrel on a hillock and, in front of numerous witnesses, it fell into the river. All attempts to get her out of the water failed.

Junior Lieutenant Maleshkin, an unshooted graduate of the school, commands the crew of the self-propelled gun SU-100. All the subordinates of Maleshkin are older than him and much more experienced. The authority of the young commander is tested at every step, he quarrels, then reconciles with his crew.