With New Year's Eve approaching, Jurek "borrows" an evening outfit (a tailcoat) from a shop mannequin at work and heads out into the city.
He accidentally helps a woman who has fallen in the street and ends up accompanying her to a New Year's Eve ball for the upper classes at the Porecki residence.
A series of funny misunderstandings lead to the guests mistaking him for the well-known and highly respected counselor Chełmoński.
It turns out that Ania's parents intend to marry her off to a so-called good match—someone with high social and financial status.
The lovers are forced to part ways, but a series of coincidences and Jurek's determination cause their fate to take an unexpected turn.