The main events unfold in the family of the head of the machine-building plant Pavel Korolenko, who was an early widower and raised his daughter Eugenia on his own. My daughter's happiness is the main thing for Paul. He dreams that Eugenia will get married and give him a grandson who will continue the family business - engineering. However, the girl from childhood dreams of becoming an engineer-inventor and, having received an education, to get a job in the office of the outstanding designer Volodymyr Gromyko.

In turn, Vladimir Gromyko ridiculed the girl's intentions, firmly letting her know that in his team, as, incidentally, in general in mechanical engineering there is no place for women. But if a woman wants something, she will definitely achieve her goal. According to her adventurous plan, Zhenya changed into a man and appeared as Yevhen Kravchenko.

A new specialist is appointed to the position of engineer in the design office. Soon Volodymyr Gromyko and Yevhen Kravchenko converge, and strong friendly relations are established between them. Vladimir is very glad that he has a like-minded person, and he even involves him in his fun bachelor adventures. However, later the events of the film unfold in such a way that the girl suddenly falls in love with her boss. And then Eugene puts into action an even more decisive plan that will turn the lives of all the main characters upside down…