A young and inexperienced fairy godmother, Eleanor (Jillian Bell), heard that the profession of fairy godmother was in danger of disappearing. She wanted to prove that people still needed fairy godmothers, so she found a letter from an unhappy ten-year-old girl and wanted to help her. But when she found the "little girl" Mackenzie (Isla Fisher), she found that she was now a 40-year-old single mother, and her life experience made her no longer believe in the "happy life". Eleanor decided to help Mackenzie find happiness whether she likes it or not.