The movie begins with Eve, played by Ann Baxter, accepting an acting award. We don't know who she is or why she's won, we just know that the guild loves her. And we meet Margo and her friends who don't applaud at the acceptance ceremony. Eve, is young with no connections. When a friend of Margo's introduces them Margo is warmed by Eve's love of the theater and her love of Margo as an actress. Margo allows Eve to work for her as her assistant and the two strike up a friendship.
Quickly though Margo grows tired of Eve. She's always around and sometimes she makes important personal decisions, like telephoning Margo's boyfriend, without consulting her first. Margo drops Eve and feels excluded by her friends who are all smitten with her.
As things begin to unravel it becomes clear that Eve is more than she appears to be. She is manipulative of everyone in the film. Eve is an actress and a damn good one. She's put on a different face for every person that she meets.
All About Eve is an Oscar winning film for one reason. It created a character who wanted something and showed to the lengths in which they would go to get that. The conflict of Al About Eve isn't terribly complicated, the cinematography isn't out of this world. But it's simple storytelling that makes the film so effective. That and Bette Davis in full form.