Katie (Lucy Hale) and Sara (Phoebe Strole) have been friends since childhood. They enter college together, where Katie is a prized legacy candidate for the Delta sorority, which was co-founded decades ago by her mother, Lutie (Courtney Thorne-Smith) and Summer (Faith Ford), whose own daughter Gwen (Amanda Schull) now leads the Deltas on campus. Events occur during pledge week to cause a rift between Katie and the Deltas, which leaves Sara as a Delta pledge and Katie out in the cold. Katie joins the rival Kappa sorority, and the rivalry splits not just Katie and Sara, but extends all the way into the Delta alumnae association led by Lutie and Summer.