After the Great War, when Megaspells rained from the skies; those not lucky enough to make it to the Stables, took to the sea. Sailing to Summer Sunset Isles resort, in hopes that such an out of the way location would be spared the holocaust. The initial refugees were cut off from the rest of the dying world by a great wall of wild weather that destroyed all that attempted to brave it. Now 200 years since, a tribal Seapony on an errand has a chance encounter that would lead to the changing of the Oceanic Wasteland forever.
The story can be found at FimFiction
The story is set in Equestria's oceans, specifically Oceania, which is home to mutant sealife such as Radsharks and various tribal groups of Seaponies. Regular pony settlements and pirates who make a living on Equestria's oceans are also present.