It takes a lot of effort to take a film which stars Rose Byrne and still make it mediocre, but, by God, director Jesse Peretz is up to the challenge.

Based on a far-fetched novel by Nick Hornby, Juliet, Naked concerns a woman approaching middle age in an English seaside town becoming slowly aware that she’s stuck in a horrible rut. Her long-term boyfriend Duncan (Chris O’Dowd) teaches television studies at a local college (and his glossary handouts for The Wire are, admittedly, hilarious), but his primary joy in life is analyzing the work of a forgotten 1990s indie rock star named Tucker Crowe.

Crowe (Ethan Hawke) released one beloved album, called Juliet, then vanished midway through a gig. Duncan and a handful of Crowe enthusiasts analyze his lyrics and trade theories of his whereabouts on a website. It’s not a hobby, it’s infatuation.

Annie (Byrne) doesn’t much care for Crowe, and she certainly is annoyed at Duncan’s obsession. When Duncan gets an advance pressing of unreleased stripped-down demos of Crowe’s classic album (the Juliet, Naked of the title) Duncan is moved to tears. But Annie just hears half-baked versions of songs she’s sick to death of. She leaves a snarky comment on Duncan’s blog saying just as much, and that leads to an email from the long-missing Tucker Crowe himself. The two begin a correspondence.

I’m gonna skip over a great deal to the bit to where Crowe ends up singing a Kinks song in the silly 1960s-themed town festival, the boozy mayor falsely introducing him as a Grammy-award winning artist. It’s reaching for that whimsical small British village vibe in movies that so frequently wins over this Yank’s heart. But I can’t remember the last time I’ve seen something fall so flat.

There’s also an awkward scene in which all of Crowe’s children (there are various mothers) collect at the foot of his hospital bed so all can bicker. Again, this is meant to show off an array of lovably “real” characters venting their frustration, but it’s all so very rote. What’s more, most of these characters aren’t heard from again, so none of this drama pays off.

Hawke is believable as the rocker and deadbeat dad, but maybe that’s just a holdover from the vastly superior Boyhood. When he slips into the wounded romantic role, it’s reminiscent of Richard Linklater’s Before trilogy. Being reminded of other, better films hardly does this one a service. O’Dowd is funny, but his character is such a putz that it’s impossible to have any sympathy for him. He’s not so much a continuation of the typical music-obsessed Nick Hornby character but a cartoon version of one.

At center, though, there’s Byrne, and good luck not falling for her charms. Annie’s frustration with Duncan, and bonding with Crowe’s young son, all hinge on such finely observed little moments. She doesn’t have loud, demonstrative scenes of hysteria: she is an intelligent, witty and well put-together woman seizing an opportunity and leaving as little destruction in her wake as possible. (To this movie’s great credit, it ends happily but not sappy.)

It’s unfortunate that Byrne’s offering such a tremendous performance in a film that is, to put it as bluntly as possible, so very dumb. I pride myself with an ability to suspend disbelief, but to do so with this story would need a crane. There are still laughs, and anything starring Byrne deserves attention, but this will ultimately end up with other demo-tape collections in the curiosity bin.