After an unsettling event in the far north, the weather in Equestria goes haywire. Snow storms from Manehattan to Baltimare, flash floods over Appleloosa, and Ponyville is experiencing the heatwave of the century. Who can answer to all this chaotic weather? Nobody in Cloudsdale. That's the weird thing. But the weather is pegasus business so it's up to them to get to the bottom of this.