Ali Hazelwood’s bestselling 2021 romance novel, The Love Hypothesis, has a setup, involving a fake-dating scheme, that genre aficionados will know well. Olive Smith is an upbeat 20-something biology grad student at Stanford University, and Adam Carlsen is a dour professor at the same school. They barely know each other, but they realize that pretending to be a committed couple has clear advantages for both of them: Olive wants to convince her best friend, Anh Pham, that she’s moved on from her ex-boyfriend Jeremy, so that Anh can date him; Adam wants to convince his department that he’s not planning to leave Stanford for another university anytime soon, so that they’ll release much-needed research funding. Olive and Adam go on several fake dates in public as part of their plan; at one point, for instance, Olive must rub sunblock on Adam’s back in a very public venue. Of course, Olive and Adam find that they have very real feelings for each other.

It’s a fun and charming love story, overall, and one with an intriguing backstory: The novel began its life as Star Wars fanfiction before Hazelwood revised it. A new Prime Video movie adaptation, directed by Set It Up’s Claire Scanlon, stars Riverdale’s Lili Reinhart and Based on a True Story’s Tom Bateman—but, sadly, it’s far less interesting than its source material. It premieres on Sept. 23.

It’s well known in the romance and fanfiction communities that Hazelwood first wrote The Love Hypothesis as a “Reylo” fic—that is, a romance starring Rey Skywalker and Kylo Ren, characters from the Star Wars film franchise played by Daisy Ridley and Adam Driver, respectively. The author reimagined the pair as academics on present-day Earth, and although the published novel changes the characters’ names, the original inspirations for Olive and Adam remain clear. For example, there are frequent references to Adam’s stoicism and impressive height (“tall as Mount Everest”), and Olive is depicted as upbeat, playful, and a bit anxious, much like Ridley’s portrayal of Rey. One can easily visualize Ridley and Driver as Olive and Adam, but, unfortunately, this was not to be—and it’s not the only way that the new movie feels less than A-list.

Part of the considerable charm of Hazelwood’s novel is how self-aware it is in its embrace of romance tropes. At one point, for instance, Adam asks Olive why she keeps using the term “fake dating” to refer to their arrangement. “Don’t you watch rom-coms?” she replies. Later, the couple must stay in a hotel room together. Despite the fact that they’ve reserved a room with two beds, she declares, “There will be only one bed, for sure….It’s always one bed.” When he disagrees, she thinks, “He’d clearly never seen a rom-com or read a romance novel in his life.”

There’s relatively little of this fun meta-commentary in the movie, which is a shame. Far worse, though, is that there’s almost no chemistry between the two leads. In the novel, the couple’s mutual attraction practically jumps off the page, which makes one notably steamy love scene even steamier. This is not the case in the film, mainly due to a remarkably wooden performance by Bateman, who never manages to be an appealing leading man; if anything, he comes off as a cold fish, at best, and self-absorbed, at worst. (The actor happens to be Daisy Ridley’s husband in real life, by the way—which, in retrospect, seems like a misguided attempt at stunt casting.) Reinhart is a fine actor with a gift for comedy, and she does her best here, but there’s only so much that one half of a rom-com couple can do on their own. A few secondary players try to pick up the slack—especially Adults’ Rachel Marsh as Anh, Olive’s fiercely confident pal—but it’s not enough to overcome the distinct lack of excitement at the film’s center. There’s an art and a science to rom-com casting—and, in this case, one wishes that the filmmakers had gone back to the lab.

David Rapp is the senior Indie editor.