This is the 12414th most frequent Polish word.
mężczyznach
"Men" (locative or instrumental plural form in Polish).
The word "mężczyznach" is in the locative case, used after the preposition "o" to indicate the topic of conversation.
Rozmawiałam z koleżankami o mężczyznach.
I talked with my friends about men.
The word "mężczyznach" is again in the locative case, as it's governed by the preposition "o" which directs the noun to be in this grammatical form.
W książce były historie o odważnych mężczyznach.
The book contained stories about brave men.
"Mężczyznach" is in the locative case due to the preposition "o," showing that the movie's narrative revolves around men.