When Kiritsugu Emiya received a call from Sella saying they had an emergency and they need to return immediately home, he couldn't help but expect the worse.

While his wife made several threats that Sella would suffer if the emergency didn't warrant cancelling their date night halfway through, all he could think of is worst case scenarios. He even considered the possibility that one of his old 'colleagues' decided to come for his family.

However, what he got was far more troublesome.

A Servant. An actual Ghost Liner was summoned by his son, who had found some of the stuff he collected in his past jobs.

Kiritsugu could only message his forehead as he and his wife sat on one side of their dinning table. The Servant was looking at them cautiously from the other side. His son, was sitting on one end of the table, looking more awkward and confused than Kiritsugu had ever seen him.

Their maids, Sella and Leysritte were standing behind the Servant, though the latter looked rather lax. His daughter, Illyasveil, a young woman with the same hair and eyes as his wife, wearing a purple button up shirt and long white skirt, was sitting on the other end of the table and currently being the only source of noise in the whole house.

That noise being her laughter.

"Hahaha! You summoned a Servant by accident!" Illyasveil held her stomach as she struggled to breath. "Oh, oh! It hurts! I can't stop! Hahaha!"

"Illya, sweetie, please don't make this more awkward than it already is," Irisveil sighed, holding the side of her head.

Truthfully, Kiritsugu didn't truly blame his daughter. If this situation had happened to anyone other than his family, he would have laughed, too.

"So... my Summoning was not intentional?" The Servant asked, looking rather lost.

"It was not," Kiritsugu replied swiftly, finally taking his hand off his forehead. "My son is not even aware of the world of Mage-craft, and I did my best effort to keep it that way."

"How are you even here?" Irisveil asked, looking confused. "We didn't hear anything about a Holy Grail War happening around our city, or any Holy Grail War, for that matter."

"Uh... Lady Irisveil," Sella raised her hand, drawing their attention. "We actually did receive an urgent letter from the Einzbern Mansion earlier today."

"What letter?" Irisveil asked, and their maid pulled a letter from the pocket of her skirt and handed it to Irisveil.

Irisveil looked at the emblem on the letter before opening and it pulling out the paper inside. Kiritsugu and the rest of the room's occupants looked at his wife as she read through the letter.

When she was done, Irisveil's face scrunched. "Oh, NOW they tell us?"

"Please tell me it doesn't say what I think it does?" Kiritsugu nearly begged his wife.

Sadly for him, Irisveil shook her head. "There's a Holy Grail War starting in Fuyuki," she stated before looking at Sella. "Why didn't you give this to me earlier?"

"I tried, Lady Irisveil," Sella sighed. "But you said that, if it isn't about the world ending, then it can wait until AFTER your date night."

Irisveil froze and shook her head. "Well... I guess we're both to blame, then"

Normally, Kiritsugu would have smiled at his wife's antics. However, he couldn't bring himself to do so.

"So, what exactly is going on?" Shirou spoke for the first time since he explained what happened. "Who is this girl? Where did she come from? What's this about a war? And what does the Holy Grail have to do with anything?"

"I am Saber," the Servant introduced themselves.

Shirou, however just blinked at her. "Your name is... Saber?"

"That's just her Class. Servants don't usually give their real names so easily," Illyasveil explained.

"Does the letter mention anything about the Overseer of the war?" Kiritsugu asked his wife. Irisveil shook her head, making him groan. "Great, that means they'll be the ones finding us."

"That's not all," Irisveil added, her expression turning even more sour. "They want Illya to participate."

"... Sella, go get me a drink," Kiritsugu ordered, resting his head on his hands. "And some medicine for this coming migraine."

As their maid went to the kitchen, Emiya turned to his parents. "Seriously, what is going on?"

"Sweetie, we have a LOT of explaining to do," Irisveil gave a tired smile to her son. "So, can you just wait until that drink comes over?"

First POV: Zack.

"A Holy Grail War?" Sakura asked as we sat down in house's living room.

"Yup. It already started, actually. Caster was already summoned yesterday and I met up with them and their Master the other day," I replied as I stared at the golden chalice on the table. I was explaining to her why we closed our café extra early.

"Oh, so that's why you left yesterday?" Sakura commented, placing a hand on her chin. "But... how can a Holy Grail War be starting?"

"I never explained how Holy Grails are made to you, did I?" I asked and she shook her head. "Well, a Holy Grail, not THE Holy Grail, but A Holy Grail, is created when the Magical energy of the world and the Magical energy of sentient life mixes together in large quantities. When it reaches a certain point, it condensates and creates a Holy Grail. That's why the most common use for them is reactors for Magical Energy."

"So why did it appear here specifically?"

"That would be MY fault," I confessed, shrugging my shoulders. "Wherever I go, the Magical Energy of the world tends to become more concentrated and pure. Henceforth it was created here."

"And why do Servants need to fight for it?" Sakura asked.

"That's the World reacting to a possible threat. A Holy Grail can be dangerous if just left around, but not even close to the same level as the Beasts of Humanity, so instead of Summoning a Grand Servant, the World Summons seven Servants to fight for the Grail using Masters as anchors. Normally, a Magus would need to step up as the Master, but if they don't, then the World itself picks the Masters or just Summons Rogue Servants," I explained with a sigh. "I'd like you to be one of the Masters."

Sakura blinked before jumping and pointing at herself. "M-Me?!"

"The Overseer themselves can't be a Master, so I can't join," I said with a shrug. "And I'd really like it if I know for a fact I can trust one of the Masters. Plus, I need your help to approach the other Masters. They're more likely to trust another Master about where the Overseer is. Caster already tried to attack me thinking I was an invading Magus."

"You're not just doing this to avoid work, are you, dad?" Sakura asked with an accusing look.

I immediately shook my head. "Are you kidding? I'm the one who has to make sure Servants don't reduce this city to rubble. Why would I avoid work?"

Sakura stared at me for a few more moments before she sighed. "Fine..."

"Alright, let's get to the Summoning Circle," I said as I got up and went to the door leading to the basement.

"You already prepared for me to Summon a Servant?" Sakura asked, following me. "What if I had said no?"

I snorted. "I know my little girl. You wouldn't have said no," my reply only got a huff from her. When we reached the basement, which was a large open space with a few utilities, a washer, and a dryer, I pointed at the large red Magical circle in the middle. "Alright, you remember the chant, right?"

Sakura nodded. She took a deep breath and stepped forward, raising her hand to the Magical circle. "Your body shall serve under me. My fate shall be your sword. Submit to the beckoning of the Holy Grail. If you will submit to this will and this reason then answer. An oath shall be sworn here. I shall attain all virtues of all of Heaven. I shall have dominion over all evils of all of Hell," the circle began glowing. "From the Seventh Heaven, attended to by three greet words of power, come forth from the ring of restraints, protector of the Holy Balance!"

The circle exploded into light. When the light died down, my puppet body completely froze and even stopped breathing.

Because I found myself, once again, staring at the most beautiful pair of eyes I've ever seen.