Umut (Emir Ozden) is a young water polo player - a gentle and quiet high school senior, just trying to live his life in a complicated world. When a fellow player spreads a rumour that he is gay, Umut, displaying maturity beyond his years, refuses to deny the allegation, apologise, or explain himself. His parents, distracted by their own marital problems, prove powerless to stem any fallout as his time at high school becomes more and more fraught - until events reach a shocking head. Set in the high testosterone world of teenage water polo, and a sometimes-suffocating Turkish society, 'Not Knowing' holds a mirror up to what it still means to be young and gay today in so much of the world.