In the world of HBO’s smash-hit House of the Dragon, marriage is perhaps the most important institution. Not because the schemers and brutes of Westeros prize love above all else. No, theirs are marital unions of political expediency and convenience, usually forced endeavors that see a young woman sold off to the son of a noble family. (Or, in the ickiest cases, the nobleman himself.) Could there ever be a lighter side to this dehumanizing practice? The new film Catherine Called Birdy (Amazon, October 7) aims to find out. 

Written and directed by Lena Dunham, Catherine Called Birdy is based on the beloved 1994 novel by Karen Cushman. In the film, Birdy (Bella Ramsey) is the free-spirited daughter of a manor-poor noble family in medieval England. Birdy’s father, Rollo (Andrew Scott), has been a spendthrift and needs some dowry money to keep his estate afloat. Thus he begins the process of marrying off his daughter, who has newly had her period, thus making her eligible. (Despite the fact that she’s just 14 years old.)

It’s the late 1200s and nothing about Birdy’s life is very nice. Everything’s muddy, her mother (Billie Piper) is forever losing babies in labor, and, because of her gender, Birdy is denied the roving, adventurous life she yearns for. And yet, Birdy rather likes the mud, and she’s got some trusty pals to cavort around with in it. There’s Perkin (Michael Woolfitt), a “goat boy” who’s always good for a bit of messy fun. On the tidier side of things there’s Aelis (Isis Hainsworth), daughter of a decrepit old lord who is perhaps more sold on the idea of romance than Birdy is, but nonetheless is empathetic to her friend’s plight. 

In adapting the book, Dunham focuses on its humor, synthesizing some of the old verve of Girls with a bit of Armando Iannucci’s arch wordplay. Characters speak anachronistically, but not as much as they do on, say, Dickinson. Free-wheeling as the movie seems, there’s a careful control at work, a restraint that prevents Catherine Called Birdy from teetering into the noxiously ironic. There’s a deep affection—a humanism, really—at the heart of the film; Dunham likes most of her characters, and thus treats them with fairness and decency. 

But is it a children’s movie? I suppose that depends on the child. If there’s a witty, perhaps slightly precocious tweenager in your life, they’d probably get a lot out of Birdy’s tale. Sure, there are some mild-ish sex jokes, but nothing on the level of what that kid is likely hearing at school. (And, of course, fart jokes like the ones in the film are for all ages.) Dunham does have instruction in mind as well. She’s altered the ending of the story from the novel, pointing it toward empowerment in a way probably not at all accurate to the time period, but not so blinkered by a contemporary outlook that we forget entirely what world Birdy lives in. 

That’s a delicate balance, and one that Dunham strikes gracefully. The film is alternately silly and sweet, cognizant of the oppressiveness of what’s being spoken about while still giving Birdy reason to play and dream and safely rebel. Ramsey nimbly maneuvers the film’s shifting tones, imbuing Birdy with an appealing mix of high-born brattiness and beyond-her-years intelligence—which we’d hate to see hidden under a bushel by some cruel transaction of a husband. 

Who Birdy really wants is her dashing, sad-eyed uncle, George (the dashing, sad-eyed Joe Alwyn), a Crusader who’s returned home to brighten Birdy’s ragged fiefdom. But George first sets his eyes on Aelis, causing a rift between her and Birdy, and then moves on to an addled-wise older widow, Ethelfritha, played with a kooky whisper by Sophie Okonedo. Catherine Called Birdy sort of gives its hero another love interest, but settling her down with the perfect boy isn’t really the movie’s mission. It’s much more a film about the assertion of self, a good lesson for any young person (or older person, maybe) as they struggle to preserve and create an identity amid all the world’s pressures and demands. 

Dunham’s ensemble of actors seems happily aligned with that goal, generously goofing around in a way accessible to kids while never pandering to them. This is an intriguing new avenue for Dunham, who heretofore has focused on the pains and erotic pleasures of later adolescence, to sometimes marvelous (most of Girls) and other times grating (the recent film Sharp Stick) effect. 

I like the more sagacious, more patient Dunham we can imagine behind the camera here. She’s refined the jaggedness of her own youthful insight and now hands down a more refined package to a new generation. True to the spirit of Birdy, though, Dunham does so in her idiosyncratic way—certainly defiant in the face of convention, but more thoughtful about the little transgressions that compromise the difficult and, yes, occasionally delightful journey toward adulthood.