In one of many throwaway scenes in Allied, Brad Pitt — playing a bland WWII air force officer and intelligence agent — is challenged to draw the “chemical formula for phosphate” or risk blowing his cover. Believe me when I tell you that (1) this is a silly test, since anyone who didn’t sleep through high school science could pass it, and (2) more troubling, this is about the only chemistry I saw on screen.

In other words, Marion Cotillard was right: Angelina needn’t have worried.

When Canadian officer Max Vatan (Pitt) is paired with comely French resistance fighter Marianne Beausejour (Cotillard) to assassinate some Nazis in North Africa, they have to play the roles of husband and wife — but along the way, by golly, they actually fall in love. Once the mission is behind them, they withdraw to London and set up a prim little wartime life, at least until British intelligence suggests that Marianne may in fact be a German spy. (No spoilers here, mes cheries — all this is safely in the trailer.)

What follows is a flat and humorless period piece that, having failed to establish any credible romance between its protagonists, limps on at gunpoint in a forced stepwise exposition of is-she-or-isn’t-she, tell-don’t-show relationship chess.

I blame Pitt. He phones this one in, distant and unemotional. Cotillard tries harder, but she’s alone in a two person game. It’s difficult to overstate the importance of a believable central love story here: not only are audiences keen to see the sparks that just maybe broke up Brangelina (you salacious rogues!), but more importantly for the movie, it’s simply critical that an “against all odds” romance actually burn bright enough to overcome all the risks. Without a solid love story, adding the layer of mistrust simply confuses things — to create dramatic tension, that spy-intrigue doubt needs to butt heads with a deep, almost irrational affection. But that’s missing. Even at the best of times, this yawn-worthy duo look like they’d hardly have swiped right on each other, let alone mortgaged their futures for one more kiss; an effort to spice up a sex scene with sudden recourse to Michael Bay-style whirling cameras left me feeling legitimately dizzy. I never thought I’d say this, but this movie needs more Nicholas Sparks.

At times, Allied comes close to being the film it wants to be. (A poignant montage, for instance, a few Casablanca-esque moments, or a brief span where it’s not immediately clear what’ll happen next.) The costumes are nice (vintage clothing hounds, rejoice!), some desert shots are very pretty, and Lizzie Caplan is good, as always. But for the most part, Allied is either unintentionally comical (over-acting extras in the background, “jolly good, old chap!” supporting characters, or a picture-perfect picnic beside smoldering wreckage) or just downright dull. And all this plays out against a rotating parade of surprisingly cheesy wartime sets. (Seriously — the sets don’t just depict the 1940s; it’s like they were built then, too.)

Director Robert Zemeckis (Back to the Future, Forrest Gump, Cast Away) seems out of his element here, lacking either quirky humor, Tom Hanks, or a volleyball. An interesting aside: Do a little digging and you’ll find that screenwriter Steven Knight (Eastern Promises) has laid perhaps the most deficient claim ever to “true story” status, claiming he heard some version of this tale from an English girl in Texas one time … about her auntie’s friend’s nanny’s Facebook friend, type thing. (He does have the good sense not to advertise it as a true story on screen.)

In all, Allied looks like something made in a genuine rush, when Pitt’s head was really not in the game. (In retrospect, we likely know why.) It’s a shame: if they’d only nailed that chemistry, Allied could’ve been much more.

Haus Verdict: A wartime romance-thriller that depends utterly on a believable love story — but at its core has only a bland, uninterested Pitt.

Allied opens next Wednesday, November 23.

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Correction: An early version of this post identified Zemeckis as the one who’d heard the story in Texas. It was Knight.