Revenge of the Storm Clan

Since Storm King's second defeat, he has gone missing. Though some assumed he drowned when being flung into the water, his two siblings, Valkyrie and Thunder, are not fooled as they claimed themselves they wouldn't kill him. Thus, until Storm King is found, the two take up the mantle as co-leaders of the Storm Clan, swearing to destroy the Lodgers and Mane Six at any cost. What will their first move be?