Brooke Cardenas (Greta Gerwig), the anti-anti-heroine of Noah Baumbach's "Mistress America," is funny, charismatic and as profoundly sad a human being as habituates American comedy. Having just turned 30, she overemphasizes her hipster bona fides whenever possible. She talks about social media in a manner her younger friends take for granted. She reacts to an intrusive cellphone in a way her new friend, Tracy (Lola Kirke) -- whose mother is marrying Brooke's father -- wouldn't even notice. ("Must we document ourselves all the time?" she sort-of laughs. "Must we?") She explains things that needn't be explained. ("I'm an autodidact. You know what that means? It's one of the things I self-taught myself.") If Flaubert were alive, and American, and had a Instagram account, he might create a Brooke Cardenas, a Madame Bovary tortured not by bourgeois boredom but a desperation for someone else's youth.
Brooke could be mistaken for an older version of Gerwig's character in "Frances Ha" (2012), the previous collaboration between the actress and Baumbach. Like Frances, Brooke is a walking lament for Manhattan and its transformation into an amusement park for trust-fund babies. But that was her movie, and story. The central character here is Tracy, a Barnard student, would-be writer, undiscovered kleptomaniac and romantic predator. Unformed and unfocused, she meets Brooke, and sees the life she thinks she wants -- the self-confidence, the power and the forward motion. Except that Brooke -- spinning instructor, band singer, sometime tutor, part-time interior designer, would-be restaurateur -- is none of those things. Tracy's admiration for Brooke will become pity.
It's probably a too-obvious comparison, but Baumbach writes with the same kind of wit and urbanity as a young Woody Allen, and the funny lines in "Mistress America" are delivered sans rimshot, and always further the development of character. What Baumbach also does is maintain the kind of understated melancholia that informs "Mistress America." The film's most captivating character (it's certainly not Tracy) is doomed, to a life of unfulfilled dreams and the precarious modern condition of always having to have new ideas and never realizing any. She's symbolic of a certain time and place, namely now, and in America.