Love has no desire but to fulfill itself. To melt and be like a running brook that sings its melody to the night. To wake at dawn with a winged heart and give thanks for another day of loving
Wings. A title. Responsibilities. A relationship with Luna. Twilight Sparkle has gotten used to a lot of things since becoming a princess. But there is still more out there for her to learn. Most especially in regards to her marefriend.
Cadance didn't know what to expect when her formerly banished Aunt Luna returned from her thousand year imprisonment in the moon. But, she's quite entertained by the hilarity.
Twilight and her friends are invited to the castle in Canterlot without any explanations. After some times, Twilight finds out what is going on, and discovers the meaning of responsibilites.
Everyone is dead. She doesn't know who is responsible, just that somepony activated the ultimate weapon. Only four ponies survived and now try to find meaning in the great wasteland. Celestia will just be happy if she can find a way to heal Twilight.
Discord, Celestia and Cadence decide that Luna is in need of serious help in courting Princess Twilight, and so take things into their own hands. Operation TwiLuna is Go!
The code of the alicorn is that only those lucky enough to be born that way will stay immortal. Those who ascend have the same life expectancy as any other normal pony. ["Will you still love me when I'm no longer young and beautiful?"]
Certain alicorns have no regard for the rules of space and time. An astral sub-dimension becomes a potent weapon in what appears to be a divine prank war. Shining Armor hits the sauce.