Guilt is the heaviest feeling there is, especially when you don’t even realize that you’re carrying it. Monstrous, which just had its world premiere at Glasgow Film Festival, explores that weight through a 1950s-set monster story featuring a strong lead performance from Christina Ricci. Written by Carol Chrest and directed by Chris Sivertson, Monstrous is an emotional film that packs plenty of mystery and horror into its portrait of a mother struggling to do what is best for her son.

Ricci plays Laura, a woman fleeing an abusive ex-husband with her son Cody (Santino Barnard). They move to California, to an isolated house that is the picture of ‘50s domestic bliss. Cody doesn’t understand why they can’t return to Arizona and reunite with his dad, and Laura reminds him over and over again that his dad hurt them and she can’t put Cody in that kind of danger again. They try to make things work in their new home, but Cody doesn’t fit in with the other kids; he is too concerned with the monster that makes nightly appearances in his room. Laura soon encounters the monster herself, and she must figure out how to banish the terrifying creature before it, too, harms her son.

There’s a delightful wrongness to Monstrous. Something feels just a little off in this world, though you can’t put your finger on what it is…at least, not at first. Senda Bonnet’s cinematography shines here, layering a pastel patina over the film and lending each scene a golden-hour glow. Laura tries so hard to make everything perfect for Cody, even though the wrongness occasionally peeks through in her dialogue: as they drive across the California state line, she tells him, “Keep an eye out for Mickey Mouse — we don’t want to run him over!” It’s a line that sounds like a cute mom joke at first, but it’s such a macabre suggestion that it sets off miniature alarm bells in the viewer’s mind. Their life may seem idyllic, with their shiny car and beautiful new home, but something disturbing lurks below the surface.

Ricci sells that tension very well: with her hidden intensity, she’s the perfect choice to bring to life the roiling emotions simmering beneath Laura’s polite exterior. Her love for her son is painfully obvious in every frame, and her secret struggles — she sneaks small bottles of vodka at night from a shoebox under her bed — resonate with viewers who understand that some emotions are just too big to face head-on. Between Monstrous and Yellowjackets, Christina Ricci proves that she is one of the best and most interesting actresses working in horror today. Her portrait of an increasingly desperate mother had me on the edge of my seat and in tears by the end of the film.

Certain plot reveals won’t come as a huge surprise to many viewers, but that doesn’t diminish the enjoyment of the film. If you view movies as shock delivery systems, this isn’t the most successful example, but if you want a well-told story that makes you feel something, Monstrous delivers. It also delivers on the horror: the moments when the monster stalks Cody are incredibly eerie, as is the scene where Laura learns just how dangerous the monster is. The film’s focus on family drama, as Laura deals with her ex-husband calling the house to try to reconcile, only adds to the tension, never detracting from the horror unfolding on-screen. 

Monstrous is a frightening and affecting story of the lengths a mother will go to in order to protect her son. With clever period details, intriguing cinematography, and eerie creature effects, the film places you in a very specific time and place to underscore the darkness hiding below the surface of this intense mother-child relationship. Christina Ricci gives a terrific performance, demonstrating the true power of a mother’s love and proving that guilt can drag you down if you refuse to acknowledge it.