The night after they defeated Nightmare Moon and rescued Princess Luna, Rainbow Dash finds Twilight on a hilltop outside Ponyville, staring up at Canterlot. Afterwards, the two find themselves returning to that same hilltop night after night, discussing their crazy adventures, and the things they've never shared with anypony else.
My entry for the 3.5 Twidash Competition.
Cover art made by me using vectors from the MLP Vector Club