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.

Engineer-geologist Svetlana Panyshko in the far northern land dreams of summer, southern sky and warm sea, but instead of vacation she is forced to take into her own hands unprofitable oil field in order not to let down her comrades and fulfill the plan.

Young engineer Pavel Kaurov goes to his first destination — to the port city of Sibirsk. He is appointed to lead a group of cranes: gantry and floating. After several troubles Pavel mastered the port work and received a serious assignment. Meanwhile, his fiancee Nina, an architect by profession, is arriving in Siberia. However, besides Pavel, fellow students came to the station to meet her — Petunin's brother and sister, in whose house she is staying. Soon Annushka, who has long loved Pavel, arrives. From that day on, he had trouble after trouble. After a crane accident, which happened through his fault, the hero pulls himself together and does everything to regain the confidence of the brigade...