Playing in the same field of thrillers starring unreliable female heroines like The Girl on the Train or Gone Girl, writer/director Michael Pearce’s striking feature debut unfurls a dark twist to the girl meets boy love story. In this case, it’s the meek Moll (Jessie Buckley), living in an isolated small town community under the strict rule of her oppressive family. Suffering at her own birthday party thrown by her harsh mother, she flees to town where she spends the evening dancing with a stranger. When that stranger won’t take no for an answer, the rugged Pascal (Johnny Flynn) steps in to save her. Their spark is instant, much to the chagrin of Moll’s family. Unfortunately, Pascal’s arrival into Moll’s life also happens to coincide with a series of disappearances and grisly murders of young women in the community. Pascal’s troubled past makes him the prime suspect.

For a while, only the score from composer Jim Williams and the sound mixing from Gunnar Oskarsson indicate that anything is really off about Moll’s new love life. So convincing are Buckley and Flynn in their innocent love that it’s easy to be lulled into forgetting that this is a thriller based in psychosis and sociopathy, save for the percussive music that reminds you there’s something sinister lurking beneath. Eventually, the realization that Moll’s perspective on her own life isn’t what it seems; she has an underlying penchant for violence and is plagued by nightmares that reveal more about her primal nature than her outward naiveté.

The issue is that Pearce keeps the gruesome murders and direct aftermath at bay while he plays up the persecuted lovers. It’s to the point that the tonal shift in the third act feels like a different movie altogether. Is Pascal truly innocent? Or, is Moll willing to accept him as he is if he is the killer? Moll’s inner struggle with these questions isn’t nearly as clearly defined as they should, favoring Moll’s own teetering grip on reality, setting her up as an unreliable narrator in her own story. When the final act does come, what should be a grim, explosive finale somehow feels like something important is missing.

Ultimately, it comes down to a lack of focus. We’re introduced to so many moving parts that it becomes too difficult to juggle, let alone give the parts much depth. There are parts introduced simply for red herrings, and many to illustrate why Moll was desperate and lonely enough to fall for someone like Pascal, even to the point of staying with a potential serial killer. Yet, almost all of the toxic relationships and moving parts introduced, very little of them have resolution. One major question is answered with a single sentence of dialogue without much fanfare. The setup becomes far more intriguing than the result.

Benjamin Kracun’s photography is stunning, and Buckley delivers a compelling performance as the lead. Her chemistry with Flynn is engaging enough to hold attention while the narrative spins out of Pearce’s control. The tonal shift undoes what amounts to one of the more interesting origins of a serial killer in the making. A thriller without much thrills, Beast is a thought-provoking character study and sort of a dark fairy tale. Moll’s story is interesting enough, but it takes too long to get there while Pearce favors quantity over quality. There’s enough here to appreciate, and Pearce will no doubt deliver better films to come, but for the most part Beast falls flat.