Author's Note: This story is based on the UBW ending of Fate/Stay Night. It is also based on the Dresden Files. It is slightly AU from the first, and Very AU from the second. I have only a secondhand familiarity with F/SN, so there may be some discrepancies as to official Nasuverse canon. All reviews are welcome.

Disclaimer: I don't own Fate/Stay Night or the Dresden Files. Rated M for violence, salty language, and sexual situations.

Prologue – Nov. 29, 20XX – LONDON

In the small kitchen of Rin Tohsaka's London townhouse, Shirou Emiya cooked happily. Delicious-smelling steam rose from a large stainless-steel pot on the stove, mixing with the aroma of freshly baked bread to create an atmosphere redolent with the scent of domestic bliss. Scarred hands and the blade-handling skills of two lifetimes combined to cleave the flesh of a yellow onion with consummate precision, carving thin ribbons to be mixed into a western-style salad in time to the quiet tune he hummed. Outside the window, a cold autumn rain blatted against the glass, while behind him at the dinner table, the Heroic Spirit Saber (also known as as Arturia Pendragon, rightful King of Britain) placed three china plates on a table already decorated with a white linen tablecloth, several picture frames, and a beautiful arrangement of flowers.

"Shirou! What should I use for glasses?" she asked, already en route to the proper cabinet.

"The nice tumblers, the red wine stems, and the champagne flutes." He chuckled, seeing Saber's arched eyebrow. "Rin went a little overboard with the anniversary plans," he elaborated, and received a fond sigh in response. "She said she'd be finished with her experiments at six, right?" he asked, glancing at the clock above the mantel.

"She should be down any minute." Saber affirmed.

Shirou nodded, swept the onions off the wooden chopping board with the flat of his knife, and moved on to an already-peeled carrot. It was true that in the past Rin had skipped meals without advance warning when she got involved in whatever ridiculous project Zeltrech had assigned to her most recently, but she had been planning this 'Tenth Anniversary Dinner" ever since she and Waver, Lord El-Melloi II, had returned from Fuyuki, the Great Grail safely disassembled.

Thinking about it, Shirou smiled. For years, the thought of the Heaven's Feel ritual had plagued the trio – knowing that the darkness of Angra Mainyu had tainted the Great Grail, Tohsaka had spent a great deal of time and energy attempting to convince the Association to discontinue the ritual and destroy all research pertaining to it. The proposal met with heavy criticism, as the Third Magic was no prize to be casually disregarded and the Einzbern family had a heavy personal stake in the War. With the assistance of Waver Velvet, Lord El-Melloi II; a man who was the only survivor of the fourth Heaven's Feel and a politically very influential person in the Clock Tower; the White Council (the Clock Tower's ruling body) had narrowly voted to destroy the grail. Rin returned to Fuyuki to supervise the destruction personally (leaving Shirou and Arturia behind to keep association experts on Noble Phantasms and Heroic Spirits from getting too close a look at them), returned home full of elation and nostalgia, and had immediately started planning a 'combination grail destruction and ten year relationship celebration'. The notoriously cheap jewelcrafter had even gone so far as to purchase high-class wine and champagne.

For his own part, Shirou had busted out his best recipes, including the most successful of his more recent experiments in baked bread (a new skillset for him, as he had grown up in an Eastern kitchen.) Rin had originally planned for a night at a fancy restaurant, but Shirou vetoed that notion with the assertion that a celebration where he didn't get to cook was hardly a celebration.

Saber, though her particular brand of skills was… not exceptionally domestic, had nonetheless exercised her meager artistic abilities to their fullest and decorated the cake with caricatures of the various Servants of the Fifth War. Saber decreed that she had first claim in being able to bite off the head of Gilgamesh, King of Kings, and if that particular piece also happened to be a little bit larger than the others, Shirou and Rin knew better than to say anything about it.

She had also filled the dining area with pictures of the three of them, the earliest dating back a full ten years, taken by an eager Taiga. In truth, little about them had changed. Saber herself not at all, of course – even had she not been renowned in life as a perpetually young king, as a Heroic Spirit her body was a magical construct and in no way subject to aging. Shirou had grown slightly taller and fuller in the shoulder; however as the container for the Noble Phantasm Avalon he was as immune to age as the king who, in life, had made it legend. In another future his imperfect ability to use the scabbard might have allowed his hair to grey and his skin to darken (and indeed Shirou had spent the occasional fretful night in the mirror after particularly difficult missions examining his hairline for signs that he might be becoming Archer) but Arturia's constant presence improved its function, leaving him with the red hair of his youth. Of the three, it was truly only Rin who had aged – once a beautiful girl, she was now a beautiful woman, poised and elegant, her pigtails exchanged for an even fall of brown hair to the middle of her back.

Turning his gaze away from the pictures on the table, Shirou added the carrots to the salad bowl and began to toss it with wooden tongs. Above his head, he heard the distinct sound of feet stamping across the workshop floor, and smirked. On the other hand, he thought to himself fondly, in some ways she hasn't really grown up at all. He exchanged a knowing glance with Arturia.

"Oh dear. Another failed experiment?" she said, placing the good silverware on the table carefully. As the angry-sounding footsteps came down the stairs two at a time, Saber stepped away from the table slightly and took a half-step forwards, balancing lightly on the balls of her feet. "… Is Tohsaka running away from the workshop? If she summoned another alternate-reality monster after I just finished decorating for this party, I'll have to punish her."

Shirou half unconsciously reinforced his hearing even as he placed the knife on the cutting board, preparing his empty hands to trace Kanshou and Byakuya, then stopped. "She's not being followed, but she's swearing in German… and she's stopped on the second floor to get changed. I guess we'll find out in a minute."

A few minutes later, a smiling Rin came down the stairs in a rather more sedate fashion, wearing a flowing black dress with a red sweater. An outside observer might have noticed nothing wrong, but Shirou and Arturia immediately noticed the tension at the corners of her eyes, her rigid posture, and the clenched fist half-hidden in the long sleeves of her sweater. She took a long deep breath through her nose and smiled, going up to hug Shirou from behind.

"Hmm, it seems I was right in allowing you to cook after all. I'll have to reward you later." Though her face was hidden from him, being firmly nestled between his shoulder blades, and her tone of voice was cheerful, Shirou could feel the tension in her embrace through his ribs. Hearing her relentless cheerfulness while he could clearly feel something wrong with her did little to decrease his concern.

Knowing that Rin only ever acted like that when something was truly wrong, Shirou prepared a quick Structural Grasping on her body to make sure that she wasn't actually injured. Anything else, he thought, and he would wait for her to tell him. "Trace… on." He muttered, pushing the tiniest bit of prana through his system.

Then he inhaled sharply through his nose, whirling to face Rin even as she stepped back, her eyes suddenly filling with tears. "Please, don't." she said, shaking her head and placing her palm on his chest. "Forget it. Just for tonight? Ne? We deserve a night, don't we?"

As Saber looked from Shirou to Rin, utterly confused, Shirou reached up and gently tugged at Rin's sleeve… revealing a trio of command seals.

In a quiet kitchen surrounded by cruel rain, in the ashes of peace and contentment, despite the efforts of all who wished to forestall it… the Sixth War for the Holy Grail had begun.