Mattie Ross is probably the last person who should be doling out good counsel to anyone on anything. Still smarting after being left at the altar two years earlier, she is strapped with debt, has sworn off men, routinely buries herself in her work and despite her well-proportioned figure, remains haunted by childhood taunts of "Fatty Mattie." But to her publisher at the Chicago Gazette, and readers, she is their latest advice columnist, The Plate Spinner, a self-assured working parent to adorable fake children and multi-tasking savant. Enter Nick Derosa, the twin brother of Mattie's cold-footed fiancé who is trying to get back on his feet after his brother steals his identity and implicates him in an illegal investment scheme. But thanks to Nick's legendary running career, the publisher of the Chicago Gazette proposes a wager: If Nick can train an out-of-shape working parent in time to compete in the Chicago Marathon, he will contribute enough to help Nick launch his own non-profit running club for kids. Suddenly "Fatty" Mattie and Nick are thrust together as the most unlikely of pairs and under a deadline to put their trust issues aside and avoid another false start in their lives.