The Lost Daughter is an adaptation of the Elena Ferrante novel about motherhood that says, quite ferociously: it’s complicated. And: mothers aren’t necessarily motherly, and can feel ambivalence. You’d think it was unfilmable, particularly as the central character describes herself as someone even she doesn’t understand but, directed by Maggie Gyllenhaal — it’s her directorial debut — and starring Olivia Colman, this film is entirely gripping.