If you are asking about the turning point of the plot, the climax, then the death of Emily is that moment. Everything is revelaed then, and the townspeople are finally able to piece together the truth of Emily's life and person based upon the remains left in the house.
The major conflict on which the plot turns is the struggle of the individual versus community. The narrator of this work is a cooperate narrator representing the townspeople. They look on with curiosity as Miss Emily lives her life, but they choose to avoid any direct contact. When they see problems such as her relationship with Homer, her dead father, or the odor coming from her house, they 'draw straws' to see who will have to deal with her, and they always choose the path of least resistance. Miss Emily continues to live in her proud and independent way making herself a mystery. She refuses any interaction as well. The refusal to interact on both sides hides the truth of the horrible conclusion until Miss Emily's demise.