Driven by the bold visual flare you’d expect from a protégé of Luca Guadagnino, Giovanni Tortorici — who served as assistant director on Guadagnino’s HBO series We Are Who We Are — makes a striking directorial debut with Diciannove. Aided by an engrossing central performance by Manfredi Marini, the film offers an unconventional not-quite-coming-of-age portrait of a 19-year-old bisexual with wavering academic pursuits, a body that refuses to process alcohol, and a libido with unusual triggers.