Somewhere in a cinematic landscape that includes Yorgos Lanthimos and Lucile Hadžihalilović lies Helena Ganjalyan and Bartosz Szpak’s “Glorious Summer,” a sun-soaked allegory filled with dread in which the customs of a curiously cloistered culture begin to be questioned. The Polish filmmakers go out of their way not to specify where in the world they are as they tell of three young women under surveillance who start to develop their own judgment inside a dilapidated mansion that’s the only home they’ve ever known, but they’ve made a beguiling debut feature that looks to put them on the map in other respects.

Appealing primarily to dedicated cinephiles, “Glorious Summer” doesn’t have much in the way of a plot, nor too many other identifying details that could make it easier to describe when the three women at the center are never named. Yet Ganjalyan and Szpak do...