On Halloween, misfit Cleo inadvertently turns her beautiful and popular older sister Molly invisible when a science project goes awry. As a result, Cleo reluctantly must agree to impersonate Molly during a crucial day at school, even as they try to reverse the invisibility. By working together and walking in each other’s shoes—sometimes literally—the sisters learn to overcome their differences and find they have more in common than they ever expected.
