British actress Romola Garai caught the attention of Sundance audiences with her stylish feature debut as a writer-director, “Amulet,” in January. The visually striking feminist horror film follows Tomaz (Alec Secareanu), a homeless refugee in London who is suffering from PTSD after serving in the military during an unnamed conflict. Garai intercuts between two stories, each of which takes a while to come into focus: the first set in the dilapidated home in which Tomaz finds shelter — from a young woman (Carla Juri) who is caring for her invalid, attic-bound mother (Anah Ruddin); and the second taking place in his past, which involved another woman (Angeliki Papoulia). Gradually, with plenty of icky atmosphere involving Tomaz’s discovery of an albino bat in the toilet (and other nasty business), “Amulet” gels around themes of motherhood, vampirism and the trauma of war. If its climax doesn’t quite deliver on the promise of its haunting buildup, it nevertheless marks the auspicious debut of a wholly original storyteller. Aided by a substantially female creative team — including cinematographer Laura Bellingham, composer Sarah Angliss and production designer Francesca Massariol — Garai’s work is made all the more memorable by Imelda Staunton, who turns a supporting role as a seemingly kindly nun into a small tour de force. R. Available at afisilver.afi.com. Contains some strong violence, bloody images, a sexual assault and brief crude language and nudity. 99 minutes.