Canterlot is expanding, and its roads are increasingly clogged by traffic. Brilliant but jaded Sweetie Belle, now in her mid-thirties, is charged by Celestia to do something about it. The Crystal Empire sends one of their top engineers to assist her. He does his best to make life awkward for Princess Twilight Sparkle while also trying to get Sweetie to lighten up. Between politics and personalities, will the beltway ever even get built?