Sunset's eyes opened to an endless field of stars. Looking around, she found herself standing in a snowy landscape that stretched towards infinity in every direction. Yet, despite the climate, Sunset didn't feel cold at all.
Up in the air, a slash of brilliant blue light split open the heavens, and a moment later a familiar alicorn appeared before her. "Luna!" Sunset rushed forward towards the princess, her forelegs wrapping around the other mare's slender frame in a crushing hug. "It's been way too long since I've seen you."
"Aye, 'tis been a long week." Luna returned the hug with equal force, pressing them close together until Sunset didn't when one ended and the other began. "I am much relieved that my sister has returned from the Summer Sun Celebration to hold court; dealing with the flood of supplicants in the Night Court has been most trying. How my sister has yet to banish Blueblood from the realm will remain a mystery for the ages."
"Well, it's over now." Sunset patted Luna on the withers in a soothing rhythm. "You can go back to holding court over a reasonable number of ponies. And I'll be with you in the waking world next week when we finally break for summer."
"I fear this coming week will stretch even longer than the one just past." Luna pulled away from the hug. "I long to see you in the flesh once again. It seems an eternity ago since your break in the springtime."
"That was fun, wasn't it?" Sunset's cheeks warmed at the memory. "Well, this time I'll be able to spend a couple months in Equestria."
"We are all looking forward to your return." There was an awkward pause as Luna looked decidedly uncomfortable. "Celestia has ordered a fresh batch of chamomile for your return."
"It's okay." Sunset gave Luna a small smile. "After all, I have one princess who knows very well that I'm a full-grown adult, and that's enough for me."
"Indeed." Luna's gaze smoldered, burning with a quickly growing heat. "Shall we prove this by engaging in a bit of adultery?"
Sunset let out a surprised laugh, her carefree voice traveling through the endless dreamscape. "I wouldn't want you thinking I'm easy," she said, her smile turning playful. "You'll have to catch me first if you want me." With that, she took off, laughing as her hooves flew across the ethereal land of frost, the sound of wings beating behind her letting her know that Luna was in hot pursuit.
Just before her lover could catch her, Sunset shifted the fabric of the dreamscape, whisking herself over to a nearby snow bank. "Didn't think I'd make it that simple, did you?" She teased, not bothering to hide her desire for the wondrous alicorn standing before her.
"Of course not," Luna replied, her own lust evident in her tone, "after all, what fun is there in easy prey?" Darkness engulfed her sleek body as she warped herself towards Sunset, taking the smaller mare by surprise and knocking her to the ground. As she pinned Sunset with her larger body, she nipped at her ears, whispering, "No matter where you run, I will find you."
Their eyes met, and as Sunset lost herself in Luna's lustful gaze, she reflected on the path she had chosen to walk. All her life, she had known that she was destined to do something great. She'd made many mistakes in pursuing what she believed fate desired for her, done great and terrible things chasing after that goal. But maybe this was how she was meant to rule Equestria all along, at the side of one of the Diarchs, sharing her body and soul with the first person to ever truly understand her.
Or maybe this was another false step, one that would lead to pain and heartache like so many others. Was she willing to take the risk? The answer came instantly and without doubt to Sunset; after all, she wasn't Twilight or Celestia, content to take the safe route in her life, to follow the immutable Sun through the endless days of summer. No, she was Sunset Shimmer, who switched between species with ease and who would ride the winter storms through the night. And she could think of no better pony to ride alongside her.
Sunset flipped the gravity affecting them until she had Luna rolled onto her back beneath the unicorn mare. "I'm counting on it." They kissed each other to seal their bond before Luna pushed Sunset off and the chase began anew, both ponies reveling in the joys of their shared fantasy.
On a hot summer night, two ponies dreamt of a better world as they played in a realm of endless possibilities, the Season of the Sun fading into memory as a new season came to pass in the history of Equestria, a season of passion and freedom and eternal winter, led by those who had hidden in shadows for far too long. The Season of the Moon and the Setting Sun.