The moral dilemma at the heart of Derek Cianfrance’s The Light Between Oceans provides the perfect platform for melodrama. This period romance, an adaptation of M. L. Steadman’s debut novel of the same name, uses its post-World War I Australian setting to pose some difficult questions; sadly, it’s too interested in politely posing those questions – and capturing some pretty landscape photography – to achieve its melodramatic potential.

Years after lighthouse keeper Tom (Michael Fassbender) and his new wife Isabel (Alicia Vikander) adopt a baby girl that arrives on their remote island by boat – along with the corpse of the girl’s dead father – they meet the mother of their adoptive daughter, Hannah (Rachel Weisz). The quandary that ensues is straightforward yet lacking easy solutions – to tell the truth means to tear a young girl from the only parents she’s ever known; to lie means to allow an innocent woman to suffer in overwhelming grief.

Juicy, huh? And the film’s last half, in which the characters’ moral mettle is tested with a string of interpersonal and legal conflicts, largely sells its tearjerker premise. But despite the heightened nature of the proceedings – lost children, racial abuse, deep questions of faith and morality – there’s an underlying emptiness that left my cheeks entirely dry. While I don’t think The Light Between Oceans is a bad film, per se, it suffers from Cianfrance’s misattribution of genre, his misguided attempts to guide the story’s heightened histrionics into a naturalistic, handsome period piece.

Of course, Cianfrance has always been so inclined. His previous films – overwrought romance-gone-wrong Blue Valentine and multi-generational tragedy The Place Beyond the Pines – were similarly hamstrung by swathing a naturalistic cloak over melodramatic material. Cianfrance’s films endeavour to tell the story of authentic working class misfortune, while hoping you forget that most working class folks aren’t Ryan Gosling or Michael Fassbender staring wistfully at a painterly sunset.

The Light Between Oceans’ problems are primarily evident in its first half. The screenplay takes its time establishing the central moral dilemma; first, we are party to a tentative penpal courtship between Tom (at the lighthouse) and Isabel (on the mainland), then their early romance, and then a pair of psychologically and physically depleting miscarriages.

The intent is to establish a baseline of character to be put to the test, but there’s something missing from these early scenes. There’s a bodice-loosening chemistry between Vikander and Fassbender – an added bonus that comes with on-screen couple fucking off-screen – but the intensity of their relationship that should result from their extended isolation on the lighthouse island never accumulates. It’s not that Cianfrance doesn’t try, gradually trading long shots for extreme close-ups and filming Vikander with handheld camerawork to capture her increasingly-unhinged headspace. But there’s too much restraint, too many handsome shots of the horizon. The conflict lurking is contrived, and opting for a discreet approach is just wrong, accentuating implausibilities and masking emotions.

The actors share some responsibility. Vikander, not so much – she understands that her role demands a degree of hysteria, which she captures without jarring with her director’s approach. Her work is not on par with what she’s previously delivered in Ex Machina or her Oscar-winning work in The Danish Girl, but it’s still good work. Fassbender, though, delivers perhaps his first underwhelming performance by relying on an internalised intensity that proves uncommunicative to the audience. The screenplay regularly feints at a crippling sense of guilt from his experience in the war, but by and large he looks constipated, rather than wracked with remorse.

The third act similarly leans too heavily on the screenplay – our insights into Weisz’s character’s headspace rely on not only a flashback to her dead husband’s words, but also a shot of her caressing a photo of him while repeating those words for audience members paying insufficient attention – but is far more successful thanks to the momentum offered by the escalating moral conflict. More than a few in my media screening were sniffing and sobbing as shit, as they say, got real, and if you’re able to forgive the fragile character scaffolding, you might shed a tear or two as well.

But it’s hard not to imagine a version of The Light Between Oceans that stops playing so coy and just swings for the fences, ramping up the emotion and the melodrama to verge towards camp. Yes, that version of the film might’ve been a disaster had it taken things much too far, but I suppose that’s just my preference: I’d prefer a movie toppling on the precipice of ridiculousness than one holding back for handsome respectability.