 Stage star Margo Channing is friend to playwright Lloyd Richards and his wife Karen, in love with director Bill Samson, and the idol of Eve Harrington who becomes her secretary-aide. Eve begins to dominate: she sends Bill Margo s birthday wishes and arranges a party for him, at which point Margo explodes. Eve becomes Margo s understudy and, when Margo misses a performance, critic Addison DeWitt gives her rave reviews while making acerbic remarks about aging actresses like Margo. At Margo and Bill s engagement party Eve tries to force Karen to get her the lead in Lloyd s new play. Margo tells Lloyd she is going to retire. Eve gets the part but Addison reveals to her he knows the lies and schemes she used to get where she is.