Shadows (2020) on Netflix

Plot summary

Their Mother insists humanity has vanished and that she, Alma and Alex must stay hidden deep in a forest, where the family survives on its own after a catastrophic event. She teaches the girls which plants heal, forbids them to step outside during the day because she says the sun would kill them, and tells them the Shadows live in the light and fill everything beyond the river that borders their home. As the sisters reach adolescence they begin to question her rules and what they know of human civilization and their own bodies; Alma has her first period. The Mother still writes messages meant for any surviving humans. Alex chafes at the control while Alma stays more obedient, and the sisters argue.