Ninja School and the True Heroes of Ninjago

AU! A chain of events sends a couple of siblings to the Ninja Academy...as servants. However there is more to them than meets the eye, and with the search for the four ninjas that are supposed to guard the legendary green ninja, they MIGHT be the key to finding them. Too bad no one notices them. After all, it is the heroes of the country you want to hear about, not the servants!