Prologue:
Long before the Royal Pony Sisters, in the reign of Queen Galaxia and King Cosmos, two more ponies reigned beside them, one an alicorn Princess Aqua Rose and the other a unicorn Prince Meteor Shower, both couples had young fillies, Celestia who had flowy pink hair, Luna who had light blue hair, Eclipse then the youngest of the girls Midnight who was a newborn unicorn filly.
One day Galaxia and Aqua were on the castle balcony of Canterlot Castle, the skies turned a dark grey "Aqua this doesn't feel right...it's supposed to be sunny all week" Aqua stared at the sky feeling negative energy quickly speaking to the queen
"go find Cosmos and Meteor hurry! and make sure the girls are safe!"
the alicorn nodded as she flew off to get the guys returning a few moments later
"Aqua! this is no ordinary storm! this is the cause of Sombra-"
"oh greeaaatt King Sombrero is back!"
Aqua gave Meteor a stern look that said 'if he hears you don't come running over to me' "what I'm just saying...okay shutting up now..."
While the four rulers were keeping an eye out outside, the fillies wanted to watch.
"Tia move over I can't see!"
"shhh Luna or we're gonna get caught then we'll be in big trouble"
"we'll be in trouble if neither of you shut it...plus if my sister wakes up my mother will come back in any way...speaking of my sister we were told to keep an eye on her!"
As Eclipse said that, the girls heard thunder from outside
"aah"
Celestia quickly looked up, her face full of fear as she no longer saw either of their parents
"Eclipse, Luna get to Midnight now! its up to us to protect her and each other!"
The filly ran onto the balcony to watch what she thought was just a storm
"mother!"
The young alicorn watched the storm as the thunder crashed around the palace, a pair of smoky eyes suddenly appeared through the clouds making Celestia run as fast as she could inside to the girls forcing herself to be strong and not tear up attempting to be brave for them all
"Tia! what happened? where are-"
Luna couldn't finish her sentence as she realized their parents won't be returning
"we...we have to look after the girls because I don't think they're coming back Luna..."
finally Celestia let her tears fall while hoping Eclipse didn't hear.