Story of animal trainers at a circus.

Pupils of the ordinary high school organize a “secret society” under the motto “Help the offended and weak, avenge widers and upstarts!” The new pioneer leader supports the children, and soon he manages to make the school life of the children truly fascinating.

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...

The accountant of the commodity base discovers a small mistake in the documents, as told by the manager of the base. That night, someone hacked and robbed a safe with accounting documents, and committed the killing of an accountant. The case for the search for criminals was entrusted to police commissioner Krechetov and lieutenant Kasyanov.