Sienna Miller and Diego Luna star as Adrienne and Matteo, an unmarried couple who just aren’t feeling the love anymore, despite welcoming a newborn baby named Ellie into the world and finally purchasing a home together. Even a night out with friends results in judgmental temperaments flaring on the car ride home over whether each is still faithful. Then their car is hit by a passing vehicle.

From there, Wander Darkly becomes something of an Eternal Sunshine–inspired out-of-body experience—quite literally—that explores where things went wrong for Adrienne and Matteo before the accident happened. After the car wreck, Adrienne finds herself in some kind of purgatory of the mind, watching her own bloody body as it is wheeled through the hospital and then cremated. She also attends her own funeral. All of a sudden, she’s back in her home, where she insists to a confused Matteo that she died, yet she’s uncertain as to how she got here and why she’s jumping back and forth through time. The boyfriend, in this case, becomes a spiritual guide of sorts, helping her get back on track. It’s this bond that helps ground the story, even as the plot unfortunately gets lost in its logical cohesion near the end.

There’s a unique non-linearity to the film’s environment as we see Adrienne experience a blend of her post-crash life and flashbacks to her early relationship with Matteo when they fell in love. The hook is that both characters are fully aware that they’re re-living the past, often psychoanalyzing memories before reenacting them alongside friends and family serving as a literal supporting cast.

Memories will often fold into one another in a manner that enhances the setting’s unreality, though some of that also stems from how Adrienne and Matteo also occasionally contradict one another on how certain events played out, subtly hinting at the obstacles that brought about their emotional and financial unhappiness. These various retrospectives allow Adrienne to undergo a reexamination of life even as she views herself as “feeling dead,” to the point that she jokingly considers the zombies of Night of the Living Dead as misunderstood kindred spirits.

Although their roles are not the most fleshed out, Miller’s and Luna’s performances are nevertheless engaging, with more than a touch of melancholic pathos. Of the two, Miller is the true star, channeling tons of emotional range into Adrienne’s struggle to move past the physical trauma of her accident, as well as psychologically reassessing her past for answers on why this relationship persisted, child aside.

The secondary cast, however, tends to seem like an afterthought, though not in a way that hinders the story. They mainly exist as figments of Adrienne and Matteo’s memories, but their lack of characterization outside of their roles feels rather jarring considering the talent hired to appear as mere plot devices. These characters work best when used as sounding boards to cross-examine Adrienne’s trauma and self-doubt. The same applies to Matteo, who, despite Luna not having as much to do character-wise, rarely makes us doubt his genuine concern for Adrienne’s well-being and fear of this purgatory consuming her sanity.

It’s also this genuineness that makes the conclusion rather frustrating. Without going into too many spoilers, the intertwined meta-memories are condensed into an outcome that’s rather linear and less subjective than what previously came before, yet we’re still meant to take its consequences seriously. The preexisting themes and strong performances remain intact, but I wish writer/director Tara Miele stuck to what she had initially built up in the first two acts in order to stick the landing.

If there’s a reason to recommend Wander Darkly, it’s for Sienna Miller. Much like her performance in last year’s American Woman, Miller manages to effortlessly convey happiness, grief, anger, and uncertainty in rapid succession to make her character’s plight feel believable enough that you remain invested. Perhaps I cared more about Adrienne for what the actress brought to the table rather than the script itself. But if there ever was a reason to bump Miller up to A-list status in Hollywood, this helps make the case.