A young man discovers that his father behaved dishonourably during wartime.

In one of the southern ports, state security authorities detained a spy with a plan for the object of sabotage — a floating dock, prepared for towing to a remote port. Major Lyudov, according to a number of signs, realizes that a whole group of enemies is operating in the city. With the help of Rakitina, the librarian of the floating dock, Lyudov and his assistant state security lieutenant Savelyev, they manage to unravel the tangle of espionage ties and prevent the crime.

A graduate of medical school, wanting to stay in Leningrad , Leningrad married - an engineer who designs bridges - Alexis. It was a marriage of convenience. However, Lyudmila, a capable student, the committee on the distribution of reserves in Leningrad, and in that time, Alex agrees to the construction of a bridge in Siberia, and demands that his wife was riding with him ...

Followed by his two sons, Chuk and Gek, an engineer-explorer heads for a geologists'camp lost in the Ural white wilderness. He plans to spend New Year's Eve there with Chuk and Gek, among his fellow-colleagues. However an undetermined incident has caused the occupiers to leave the place. When, to their amazement, the three adventurers discover the empty camp, they realize that they don't have enough food to return immediately and that they will have to join forces to survive for a few days without any outside help...