Richard Crouse

“Rosaline,” a new romantic comedy based on “Romeo and Juliet,” alters the dynamics of William Shakespeare’s play by flipping the script to focus on Rosaline (Kaitlyn Dever), Romeo Montague’s ex-girlfriend. “The greatest story ever told,” she says, “was missing a chapter. Mine.”

Based on Rebecca Serle’s young adult novel “When You Were Mine,” which was inspired by Shakespeare’s romantic tragedy, the Disney+ movie sees Kaitlyn Dever play a character who is mentioned but never seen in the original play. She is Rosaline, Romeo’s (Kyle Allen) girlfriend, at least she is until her cousin, Juliet Capulet (Isabela Merced) shows up.

Turns out Romeo uses his trademarked flowery romantic language to seduce Juliet. “I’m afraid you’re not the first maiden he’s charmed with his high cheekbones and fancy words,” says Rosaline.

Distraught, Rosaline is determined to break them up, and win back her man, even as a possible new romance with Dario (Sean Teale) brews. “Romeo and Juliet,” she snorts, “It doesn’t even sound right.”

These times of woe afford no time to woo, indeed.

Like “A Knight’s Tale” or the recent “Catherine Called Birdy,” “Rosaline” is a medieval period piece presented with modern sensibilities and idioms. The iconic balcony scene, for instance, is there, but tweaked for laughs, and at one point the morose Rosaline uses cholera as an excuse to not get out of bed.

Even the play’s famous ending has been spun. No spoilers here, but it should be noted that “Rosaline” isn’t exactly a romance and it isn’t a tragedy. It’s more a heartbroken journey of empowerment and self-discovery.

It doesn’t all work. The story slows in the middle, and, for older viewers the high school romance aspects may get old quickly, but at the heart of the story is Dever. As the title character she is both vindictive and vulnerable, a young woman with an attitude and a big beating heart. Her recent work, heavier turns in the film “Dear Evan Hanson” and TV dramas like “Dopesick” and “Unbelievable,” haven’t showcased her comedic talents, but “Rosaline” gives her the opportunity to stand out in the midst of the movie’s screwball co-incidences and farcical aspects.

Strong work from Bradley Whitford as Friar Laurence—who scolds his daughter with, “You are a woman. You’re not supposed to talk about what you want!”—and “Good Will Hunting’s “Minnie Driver as the outspoken Nurse, round out the cast.

“Rosaline” is no “Rosencrantz and Guildenstern are Dead.” Tom Stoppard’s absurdist, existential tragicomic “Hamlet” riff examines the mystery of life. “Rosaline” sets its sights lower. It is a high school romance in a corset that should work for fans of “Romeo and Juliet,” the Coles Notes version.