Weird sisters have been spinning their witchy webs in stories dating back to Greek mythology, which included a macabre trio of sisters who passed a single eye between them. There is something of that sense of a closed circle of unknowable femininity between the two teenage girls in September Says, the first film to be directed by Greek Weird Wave actor Ariane Labed, based on the 2020 novel Sisters by Daisy Johnson and set between England and Ireland.

July (Mia Tharia) is timid, a new girl at the high school where her sister September (Pascale Kann) already is marked as unruly, aggressive and peculiar, inclined to bullying; she will appoint herself as her sister’s protector. July is relieved to hang back, even when there is a hint that her sister’s control-freakery might include commanding the weather. There is a whiff of the witch about her, too.

The two girls are of Indian extraction,...