The year is 2033. This is Equestria. A land of death and poison. The ponies have hidden themselves in the Metro for the past twenty years, but now a new threat has appeared that can damage their hopes of returning to the surface forever.
After months being a Princess, Twilight Sparkle is back in Ponyville. While she's trying to piece her old life back together, a new entity arise from the shadow, threatening to collapse realty in on itself.
The Rainbow family has thousands of family members in its history, but Rainbow Dash is going to find out something she never even knew, something her parents never told her. She had a brother. Looks like she isn't a lone child, after all.
After a stunt goes haywire in her very first Wonderbolt air show, Rainbow Dash will learn the true reason for her being the only "rainbow maned" pegasus around.