The lingering trauma shared by two middle-class families, once friendly but now estranged following a tragic camping incident, is finally addressed through the unlikely prism of a high-school drama club production in “Between Us,” Shingo Matsumura’s well-intentioned, yet only fitfully successful, exploration of unprocessed grief. The writer-director’s fourth feature film premieres as part of the Tokyo Film Festival’s revamped and newly competitive Nippon Cinema Now section and is bolstered by a quartet of assured performances from its female leads.

Ririka Kawashima is most impressive as the shellshocked teenager Makoto in a story that sees mothers and daughters emerge from the emotional fallout of losing a loved one to shoulder the burden of recovery and reconciliation. Never lacking in ambition, yet left somewhat wanting in execution, commercial prospects for “Between Us” may well be limited to specialist showcases with a particular focus on nurturing emerging voices still honing their craft.

In a brief yet crucial prologue, 10-year-old Kasumi and her parents set out on a countryside camping trip. They were set to be joined by Kasumi’s classmate Makoto and her family, but she is sick and her father is called into the office unexpectedly. As a result, only Makoto’s eight-year-old brother Kenji goes with the other family, and upon arrival at the campsite, scampers around excitedly with a butterfly net, while being warned not to wander too far.

Six years later, and the domestic landscape has changed dramatically for both households. High-schooler Makoto (Kawashima) lives with her mother, Emi (Akiko Kikuchi) — who is now an emotional wreck — while her father (Yoichiro Saito) has moved out, lost his office job, and now scrapes together a living as a delivery driver. Makoto bristles when an elderly neighbor casually mentions her brother, while Emi becomes all but catatonic when a colleague at the library where she works asks after her “little one.”

Kasumi (Anna Kurasawa) and her family appear to be faring somewhat better. They are still together and have added a now five-year-old daughter, Chika, to their brood. But when mother Fumiko (Asami Usuda) comments that their youngest was complaining about never seeing her father (Takahiro Miura) smile, the cracks beneath this veneer of domestic bliss quickly become apparent.

These early sequences display a keen ability from Matsumura to paint a tragic picture of malignant, festering grief from a past tragedy, without the need for any overt explanation. However, in a frustrating and unnecessary misstep, an out-of-place news report on a car radio confirms that Kenji disappeared on a camping trip with family friends six years earlier, and that the police have not ruled out the possibility of foul play. Not only does this heavy-handed over-clarification — beyond earshot of any character and included solely for the benefit of the audience — erase any sense of mystery surrounding what has happened, but it also suggests a forthcoming procedural element to the narrative that never materializes.

Instead, the film turns its attention to Makoto and Kasumi, who find themselves not only attending the same high school, but enrolled as sole members of the school’s struggling drama club. Simultaneously, Fumiko and Emi cross paths at the library, where the revelation that the family at least tangentially responsible for her son’s death now have an adorable little sprog of their own, threatens to send Emi into an emotional tailspin.

While both patriarchs prove utterly ineffectual in processing what has happened, and their wives reluctant to engage, it falls to the younger generation to acknowledge the suffocating sense of loss that has smothered and crippled both families. Makoto and Kasumi resolve to produce a play dramatizing precisely this decision to reconcile, leaning into the residual affection they still hold for each other and, unlike their parents, a desire to process the hostility that has manifested in the hope of letting go and moving forward.

As it crawls timidly towards its climactic performance, “Between Us” frustrates as frequently as it impresses, teasing at promises of meta-textual experimentation or cathartic revelations, precious few of which come to fruition. In many ways, Matsumura’s film recalls Lee Jong-un’s 2019 Korean drama “Birthday,” which observed the paralyzing impact of the 2014 Sewol ferry disaster, in which more than 300 people died, without ever reenacting the event itself.

The director’s resolve to leave crucial questions unanswered is bold and praiseworthy, but he might have gone further still. Similarly, his stance that his teenage heroines are more willing and better equipped emotionally to forgive, heal and reconcile than their parents might have benefited from a modicum of conflict or pushback from the older generation. Nevertheless, despite these shortcomings, “Between Us” remains a tidily assembled little package that brandishes a welcome glimmer of dramatic ambition, and at the very least, provides its female cast with a stage on which to shine.