This is how Prologue: A tale of regal sisters goes in My Little Pony Transformers Prime: Friendship is Magic.
[We begin with a book with a golden unicorn head on it's cover. It opens by itself, revealing the words "Once upon a time...". As we zoom in on the book, the pages in it come to life]
Narrator: Once upon a time, in the magical land of Equestria, there were two regal sisters who ruled together and created harmony for all the land. To do this, the eldest used her unicorn powers to raise the sun at dawn; the younger brought out the moon to begin the night. Thus, the two sisters maintained balance for their kingdom and their subjects, all the different types of ponies. But as time went on, a unicorn pony named Thunder Streak became resentful. The ponies relished and played in the day that the elder sister brought forth but shunned and slept through the younger sister's beautiful night. One fateful day, due to him being the only one who really knew the younger sister's night, Thunder Streak refused for the younger unicorn to lower the moon to make way for the dawn. The elder and younger sisters tried to reason with him, but the bitterness in the unicorn's heart had transformed him into an evil tryant and follower of Unicron: Thunderwing.
[We see Thunderwing against a red background]
Narrator: He vowed that he would shroud the land in eternal night and plunge it into chaos. Reluctantly, the elder and younger sisters harnessed the most powerful magic known to ponydom: the Elements of Harmony. Using the magic of the Elements of Harmony, they defeated the follower of Unicron and banished him permanently in the moon. The elder and younger sisters resumed their responsibilities for raising both the sun and moon and harmony has been maintained in Equestria for generations since.
[We cut to a red and blue armored Transformer named Optimus Prime reading the book]
Optimus Prime: Hmm. The Elements of Harmony. I think I have heard word of these magical relics somewhere before. But where?
[Optimus Prime walks out of the library he's in and heads to the Hall of Records when he runs into Stringer, Blurr, and Jazz]
Stringer: There you are, Prime.
Blurr: We were just looking for you.
Jazz: Cyber is having a little get-together in the west castle courtyard. You wanna come?
Optimus Prime: Uh, I would love to participate, Jazz. But I need to check something out first.
[Optimus transforms into vehicle mode and drives away]
Stringer: Sheesh. I wonder what he wants to check out this time.
Blurr: Don't look at me.
Jazz: I think he's more interested in checking things out than friends.
[Optimus drives on]
Optimus Prime: I know I've heard word of these relics.
[Optimus drives towards the Hall of Records where he finds Ratchet, Bumblebee, Arcee, Bulkhead, and Smokescreen hanging out]
Bulkhead: Hey, Prime.
Ratchet: Where have you been?
Smokescreen: We already started our game of lobbing.
Bumblebee: [beeps] (translation: What took you so long?)
Arcee: We've been waiting for the past 4 hours.
Optimus Prime: Autobots, I have heard word of relics called the Elements of Harmony somewhere before. But my only wonder is where.