It’s so bold an approach that it deserves some credit, and perhaps the junky science is a deliberate move that contributes to the film’s determinedly vintage filter, just like Lively’s Katharine Hepburnish affect and her 1940s updos. The central conceit might be ridiculous, but it’s hard not to be swayed by the earnest nature of the storytelling, or by the lush, romantic visuals conjured by director Lee Toland Krieger. The movie wouldn’t be out of place among the more creatively whimsical magical-realism films of the 80s and early 90s; fables like Edward Scissorhands, or The Goonies, or Field of Dreams. But by trying to ground its fantastical elements in science—bandying around terms like “anoxic” and “deoxyribonucleic acid”—it loses some fairy dust, and sets itself up for the cruel scrutiny of the Internet age. Adaline might be a gentle soul who belongs in a more innocent time, but most cinemagoers, sadly, are not.

The film meanders slowly through its first hour, unveiling Adaline’s backstory with meditative somberness, and introducing her to the obligatory handsome stranger, Ellis (Michiel Huisman), who developed an algorithm in college to analyze climate data that ended up being a handy financial forecasting tool, making him a gazillionaire in the process. It also reveals how, at the age of 45, Adaline’s youthful appearance made her a target for the FBI, who attempted to take her away for “some tests.” The prospect of being “a curiosity” leads her to abandon her now-grown daughter and start a new life on the run, making friends only for as long as she can keep them from becoming suspicious, and—after one significant mistake—avoiding love affairs altogether.

Lively doesn’t really show her potential as a leading lady until the second half, up until which her clipped delivery and coy restraint feel a little like Turner Classic Movies interpreted by Saturday Night Live. But as the emotional intensity ramps up, she proves herself to be a capable performer. The most moving scene in the film comes when she goes through a box of old things and opens a photograph album filled with mementos of all the souls she’s loved and lost—only instead of humans, they’re identical King Charles spaniels. (Eighty years staying the same age amounts to something like 560 dog years.) And her chemistry with Huisman is stirring, although her chemistry with his father (Harrison Ford) makes them perhaps the more intriguing onscreen pair.

The Age of Adaline hints at, but never fully explores, a wealth of potentially mind-blowing and comical setups. Adaline’s daughter, for example, is played by Ellen Burstyn, and the pair engage in a number of role-reversed arguments about assisted living and sodium and romantic relationships that prove fascinating thanks to their odd dynamics (to both actresses’ credit, the relationship is somehow a believable one). Her one enduring friend is a blind woman who assumes they’re the same age and tells mystified suitors to ignore the two old crones at the table while Adaline looks on, shrugging. “That’s the last photograph I have of you,” says Burstyn’s character, Flemming, of a snapshot taken many decades ago. “Well, you’ve seen one, you’ve seen them all,” replies Adaline, drily.