On paper, The Spy Who Dumped Me is the kind of breezy but satisfying entertainment made for unwinding on a summer night. On paper, its story of female besties realizing their full potential by crisscrossing Europe, running away from bad guys, undergoing lavish makeovers, and squaring off against an enemy in midair during a Cirque du Soleil trapeze act is an occasion for a girls’ night out planned weeks in advance. On paper, the pairing of comic dark horse Mila Kunis and Saturday Night Live breakout Kate McKinnon—an unexpected union between a tactical Swiss army knife and a lopsided bouncy ball—gives us a new comedy duo that feels fresh, contemporary, and relatably off-kilter.

I kept imagining an alternate version that knew how to deploy its supporting players instead of treating them with the same indifference that James Bond shows his knee cartilage.

But in practice, The Spy Who Dumped Me, directed by relative newcomer Susanna Fogel (whose first film was the 2014 indie Life Partners) and co-written with TV scribe David Iserson, smothers its enormous potential until it turns blue. Filmmaking is a process made up of thousands of decisions, and too many of the ones that led to this action-comedy, particularly in the journey from page to screen, were wrong turns. The premise is rock-solid: Aimless supermarket cashier Audrey (Kunis in a Hawaiian shirt, if you’re into that) discovers that the boyfriend (Justin Theroux) who recently broke up with her via text is actually an undercover CIA agent and resolves to deliver a package in his stead after a mercenary’s bullet leaves him dying in her arms. She takes her friend Morgan (McKinnon), an unemployed actress, to the handoff location in Vienna, because while it’s not exactly considerate to put your BFF in harm’s way, would you wanna go alone? Fleeing cafe shootouts and a model-assassin (Ivanna Sakhno) who enjoys incorporating gymnastics routines into her torture sessions (a great girly touch!), the women play spy games until they realize they’ve leveled up from novice to expert.

But the setup falls apart almost as soon as it’s constructed. Partly to blame is the choice to go down the R-rated studio-comedy checklist and fulfill every item. An uncanny resemblance to a much better comedy from a few years ago? Check. A pushing-30 existential crisis? Check. Pointless diarrhea? Check. A brief and gratuitous shot of dong? Check. Grisly yet tedious violence? A shockingly casual attitude toward murder? Paeans to friendship as hollow as lunar craters? Check, check, and check. It doesn’t help that Kunis and McKinnon share zero chemistry, thus sucking the air out of each scene in which they’re supposed to be bonding. Hard-edged Kunis is unmistakably miscast as a harmless everywoman. McKinnon is given the same weirdo role she played in Ghostbusters and Rough Night—the fast-thinking, overconfident flibbertigibbet who seems to have one foot in our universe and the other somewhere else. But the comedian doesn’t get the breathing room to unfurl all her kookiness at her own pace. Lines that should be funny are sacrificed to the breathless exigencies of the plot. The movie starts to feel like a slow suffocation.

It’s revealing, and disheartening, that The Spy Who Dumped Me’s most memorable scenes have little to do with the leads’ performances. A couple of jokes at the expense of American tourists—one in a gun-filled hostel room, the other surveying a picturesque European capital full of vomiting backpackers—display a winking self-awareness of the difference between movie Americans in Europe and actual Americans in Europe. And if you head to the theater already aware of McKinnon and Gillian Anderson’s mutual adoration, you’ll find plenty of charm in the scene in which Morgan can’t help slobbering over Anderson’s MI6 chief. But without that context—or Anderson having much to do other than look fantastic in skintight office dresses—Morgan calling this latter-day M “the Beyoncé of government” is just another not-quite-funny line hitting the ground immediately after launch.

Even as I felt increasingly worn down by The Spy Who Dumped Me, I stayed impressed by its sturdy foundation. I kept imagining an alternate version that knew how to deploy its supporting players—Sam Heughan as the love interest, Hasan Minhaj as the irritating mini-villain, Jane Curtin and Paul Reiser as the folksy parents—instead of treating them with the same indifference that James Bond shows his knee cartilage. I envisioned what it might be like for the script’s emotional beats to actually land (as weightless as the individual arcs for Audrey and Morgan may be) and its good intentions to be supported by effective execution. Accepting the mission is one thing. Achieving the objective is quite another.