The stately and subdued drama The Souvenir stars Honor Swinton Byrne as Julie, a quiet but passionate aspiring filmmaker making her way through film school in early 1980s England.

While snapping photos at a party one evening, she meets the older and seemingly wiser Anthony (Tom Burke) and after a series of initial dates, the two move in together and begin a romantic relationship. We then see snapshots of their life together, from the promising sparks of humor and shared interests between the couple to the seeds of discontent that are sown from deceit and over-dependence.

Around the mid-point of the film, Julie discusses the technical aspects behind the classic shower scene from Hitchcock’s Psycho with her film school colleagues. It’s fitting, then, that The Souvenir feels like the emotional equivalent of that very scene played out in super slow motion, as we watch a budding romance gradually decay over the course of two hours.

“Gradually” is very much the operative word in this case, as the deliberate and sometimes lugubrious pace of the narrative is both the film’s most notable and most frustrating creative decision.

The Souvenir would seem to be, at least in part, an autobiographical tale from English writer/director Joanna Hogg, who attended film school in her mid-twenties just like the film’s heroine.

The sense is that this is Hogg’s way of reckoning with a toxic relationship from her youth, a foggy look into the past realized with fittingly hazy camerawork from cinematographer David Raedeker.

While this experience may well have been formative for Hogg in her personal or professional life, the significance of the “tragic love story” at hand is obscured further as it drags on to its inevitable conclusion.

Though the direction comes off as incohesive and haphazard, what kept me thoroughly invested through most of the runtime were the terrific performances by Burke and especially by Byrne. Sporting an initially alluring dry wit and near-permanent sneer, Burke is properly detestable as the passive-aggressive leech that latches himself to our naive protagonist.

Byrne, the real-life daughter of powerhouse actress Tilda Swinton (who also appears briefly in the film as Julie’s mother), is even better in a star-making turn that will hopefully earn her plenty of work in the future.

The film’s best scene, in which a character played by Richard Ayoade relays to Julie some portentous details about Anthony, allows Byrne to play stages of heartbreak in a series of dynamically framed reaction shots.

The central question most audience members will no doubt have while watching this film is, “Why doesn’t she just break up with this guy?” Hogg’s sly inclusion of the pop song “Is She Really Going Out With Him?” implies that she anticipates this reaction.

The issue is that the answer to these inquiries is never relayed convincingly and is often sidetracked by inert scenes involving Julie’s film project that distract from the narrative at hand, particularly in the film’s second half.

Hitchcock once quipped that “drama is life with the dull bits cut out.” In the case of The Souvenir, it seems Ms. Hogg left too many of them in.

Coming to theaters this weekend

Toy Story 4, starring Tom Hanks and Tim Allen, brings the toys back together one more time as they head out on a road trip adventure with a new toy named Forky.

Child’s Play, starring Aubrey Plaza and Brian Tyree Henry, reboots the 1988 slasher film about a murderous robot doll who terrorizes a mother and her teenaged son.

Anna, starring Sasha Luss and Luke Evans, is the latest action thriller from Léon: The Professional director Luc Besson about a fearless government assassin on a dangerous new mission.