Ever wonder why Granny Smith gives Filthy Rich those 100 jars of zap apple jam? Or who her husband is? Or why zebras are treated differently in Ponyville? All the answers are in Granny Smith's private scrapbook.
In Equestria, there are two clans in the north, the Rebel changelings, and the Sea Ponies who disguise themselves as Pegusi. These clans have fought for thousands of years, and two ponies try to put a stop to all the fighting.