The titular siblings of Hal & Harper are inseparable, their co-dependency unmistakable. Hal (Cooper Raiff) is constantly perky and animated, relying a tad too much on his elder sister, Harper (Lili Reinhart🅠). She displays the occasional grouse but ultimately ungrudgingly remains one he can fall back on practically anything. A long-delayed college assignment? Sure, she will take it up. He crashes at her place at any time. She sets aside her inconveniences. Hal & Harper, written and directed by Raiff, establishes textures of their relationship with instant ease, the sort of pleasurable, fractious familiarity that can only come with knowing your characters like the back of your hand.