The young lovers of Before Sunrise (1995) and Before Sunset (2004) return, but now they’re middle-aged parents; in fact, this third installment in the beloved indie series opens with a near parody of its endless walk-and-talks in which the characters (Julie Delpy and Ethan Hawke) drive through the Greek countryside hoping their two little girls in the backseat won’t wake up. The first movie was a prolonged flirtation and the second a romantic reunion; this one is a slowly evolving quarrel between two people who know each other inside out, delivered with the same intelligence and discernment but, as you might imagine, something of a cold shower. Richard Linklater directed a script he wrote with Delpy and Hawke; you have to give them credit for keeping this real, though I have visions now of the series concluding with “Before Chemo.”