Gantung: Musketeer Code follows Khalil, a renowned film director, who is called back to his former school by an old friend, Farah, to settle an unresolved matter. He is forced to confront a tragedy from ten years ago, when he and three of his closest friends were accused of causing the death of a student named Ratna. As they attempt to clear their names, a series of strange events begins to unfold, leading to a shocking discovery about the true cause of the tragedy - and a secret that changes everything.