The Equestrian Flood

Equestria has been heavily affected by overflows of water, as people like Seaquestria, Equantica, and many other underwater civilizations, have been feeling a dark presence in the ocean, and it's not Squirk as they previously thought. Turns out, it's far worse: a monster capable of massive floods known as a Leviathan, in it's traditional form as a giant fish beast, had been released from it's Tartarus Prison, and has gone into the oceans and causing water levels to rise. They have to now not only stop the Leviathan, but find whoever released it. They later find who did it: another relative of the Storm King called The Typhoon King, whose powers of manipulating water are 'unfathomable' in his words, as he has used the Leviathan to avenge his family by flooding all of whoever caused them to crumble in the first place. Thus, the heroes must do what they can to stop this flood from destroying Equestria and drowning everypony in it.

(Reintroduced from it's previously deleted version to fit the Season 4C's conflict)