Author's Note: Honestly, I have no idea what went through my mind when I was writing this...

Shirou was walking down one of Chaldea's hallways, minding his own business. However, as he was walking, he came across something that was on the ground.

"Hm? What's that over there?" Shirou thought as he was walking to the object that was on the ground in the distance. As he got closer, he saw what the object was.

It was an envelope, and it had some wax that was shaped and had a design on the wax that sealed the envelope shut.

"Hm? An envelope? What's an envelope doing here? And this wax seal...it looks nothing like any wax seal I've ever seen. Did Da Vinci drop one of her things again? Well, I might as well return it to her..."

However, before he could so, the invitation suddenly lit up, surrounding itself and Shirou in a bright light.

"What the?! What's going on?! What is this light?!"

And in an instant, both Shirou and the envelope were gone, with no trace of them left in sight...

Ritsuka and Mashu were heading towards the cafeteria for lunch. As they arrived however, they heard a few voices coming out of the cafeteria.

"Hey, has anyone seen Emiya-kun?" Ishtar asked as she was drinking a cup of tea.

"Nope. I haven't seen Shirou," Arturia replied as she continued to eat her bowl of rice.

"That's strange. Usually, senpai would be here right now, but for some reason, he isn't," Parvati said.

"Onii-chan, where are you..." Sitonai muttered.

"Sherou, it's rude to keep a lady waiting..." Astraea muttered.

"Shirou, where are you? I'm starving..." Jaguar-man muttered.

"That's odd. Usually, Shirou would be here at this time of day, but he's not for some reason...is he late? Or did he oversleep?" Irisviel said.

Ritsuka overheard the voices in the cafeteria and thought, "That's odd. Shirou isn't here yet. Did he oversleep? Or is Da Vinci hogging him again for her experiments?"

"Senpai. Is there something wrong?" Mashu asked, snapping Ritsuka out of his thoughts.

"Well, it seems that Shirou isn't here at the cafeteria yet," Ritsuka replied.

"Eh? He's not here yet? Even though it's already this late?"

"Yeah. Maybe we should check on them and see."

"Good idea."

The two then headed into the cafeteria. "Hey there everyone," Ritsuka said with a smile on his face, attracting everyone's attention.

Arturia then got out of her seat and said, "Master, where is Shirou?"

"Shirou? I don't know. Why?" Ritsuka replied.

"Well, it's already lunchtime, and Shirou's not here yet. Have you seen him earlier?"

Ritsuka thought about Arturia's question and said, "No. I haven't seen him. He's not here yet?"

"Yeah."

"Well, that's odd. Usually, Shirou-san should be here right now," Mashu said.

"I know right?! Just where is that idiot!?" Ishtar yelled.

"Now, now, just calm down," Parvati said, trying to calm down Ishtar.

"Yeah. Maybe Sherou has some business to finish," Astraea said.

"Still though...it's not like Shirou to be this late..." Jaguar-man said.

"Master, if you find my son, can you tell him to get over here?" Irisviel asked.

"Sure," Ritsuka replied.

"Great! Now hurry up and find onii-chan!" Illya said.

"Y-Yes!" Mashu said. She and Ritsuka then left the cafeteria in a hurry to find Shirou. "Wow, that's the first time I've ever seen Ilya-san so pushy..."

"Yeah. I guess when it comes to her big brother, stuff like that could happen..." Ritsuka said.

"Maybe. Anyways, let's find Shirou-san by walking around and asking the other servants who know him where he is."

"Good idea."

Ritsuka and Mashu then started walking in the hallways to find Shirou. As they did, they also ended up with the first servant they saw nearby that knew Shirou.

Cú Chulainn, Ireland's Spear of Light.

"Hm? Oh, hey there master. Young lady. What are you two doing here?"

"Cú-san. Have you seen Shirou-san around here?" Mashu asked.

"The kid? Why?"

"Well...it's already lunchtime, and he's not in the cafeteria. Arturia, Ishtar, Parvati, Illya, Astraea, Irisviel, and Jaguar-man wanted me to find him and tell him to go to the cafeteria," Ritsuka replied.

"Oh. Well, I haven't seen the kid around here. Try asking his alternate counterparts. They should at least have a clue where he is because well, they're him."

"I see. Thanks for the advice Cú!" Ritsuka said.

"No problem! By the way, if you see the kid, tell him I want a rematch!"

"Will do!"

Ritsuka and Mashu then went on to find either EMIYA or EMIYA Alter in the hopes of them knowing where Shirou was. Eventually, they found EMIYA, who happened to be walking down by a nearby hallway. "Hey EMIYA!" he yelled.

EMIYA turned around to see Ritsuka and Mashu coming at him. "Master? What are you doing here?"

"EMIYA. Have you seen your younger counterpart around here?"

EMIYA thought about Ritsuka's question and replied, "No. I haven't seen him. Why?"

"Well, it's almost lunchtime, but Shirou-san isn't in the cafeteria now. We asked Cú-san where he is earlier and he told us to find you because you might have a clue of where he is right now considering that...well, he's you," Mashu replied.

EMIYA let out a sigh. "I see. Anyways, like I mentioned earlier, I haven't seen him. You might want to check somewhere else, because right now, I have no clue where he is now. Try asking Da Vinci next and see if he's with her. You know how much Da Vinci likes using him as a guinea pig for her experiments."

Both Ritsuka and Mashu shuddered a bit at the last sentence EMIYA said. "Good idea. Let's try her next Mashu."

"Y-Yes! Thanks for the advice EMIYA-san!" Mashu said.

"No problem."

Ritsuka and Mashu then left for Da Vinci's workshop, leaving EMIYA alone.

"Well then, looks like I need to go to the cafeteria right now. But seriously, where is my younger self at a time like this?"

Da Vinci was in her workshop, inventing a new mystic code that came from her head. "All right! Once I'm done with this, I'll ask either Ritsuka or Shirou to test it out for me!" she thought excitedly. After a few more minutes of tinkering, Da Vinci was done with her invention. "Perfect! Now, all I need is for either Ritsuka or Shirou to help me test it out!"

As Da Vinci looked at her newly created invention, it was then that she heard a few knocks on her door followed up a certain voice she wanted to hear.

"Da Vinci? It's me, Ritsuka. I need to ask you about something."

Da Vinci let out a smile. "Perfect!" she thought as she went up to the door immediately. As she opened the door, she saw Ritsuka and Mashu in front of her. "So, what do you need to ask me for?"

"Da Vinci, have you seen Shirou-san around here?" Mashu asked.

Da Vinci was confused for a moment. "No. I haven't seen him yet. Why?"

"Well, it's lunch time right now, but Shirou isn't in the cafeteria now," Ritsuka said.

"Really? One of the head chefs of Chaldea isn't at the cafeteria. Has the world gone mad?" Da Vinci jokingly asked.

Ritsuka let out a sigh. "This is no time for jokes Da Vinci. Was Shirou here earlier? EMIYA said that he would be here sometimes."

Da Vinci shook her head in response. "Nope. I haven't seen him. However, I could check Chaldea's security system to see where he is. Would that be okay for you?"

"Y-Yes!" Ritsuka and Mashu said in unison.

Da Vinci let out a smile. "Well then, come on in."

Ritsuka and Mashu then went into Da Vinci's workshop and followed Da Vinci to her desk. As they did, Da Vinci then sat on her chair, pulled out her laptop, and began to access Chaldea's security systems. "All right, let me access the footage so that way we can see where Shirou is."

Ritsuka, Mashu, and Da Vinci looked at the laptop screen and saw all the footage in Chaldea's security system. They checked every camera screen and didn't see Shirou anywhere.

"Well, that's odd, he's not in any of the footage," Da Vinci said.

"Eh?! Is that even possible?!" Mashu asked.

"Well yeah, if he is in his room. Speaking of which, did both of you check earlier?"

"Yeah. We did earlier, and when we checked, he wasn't even there," Ritsuka replied.

"I see. Well, if that's the case, then let me check past footage of today and see what happened to him." Da Vinci then accessed the security's databank and checked on earlier footage that happened today.

As so, all three of them were shocked with the footage of what happened to Shirou.

In which he picked up an envelope...and suddenly disappeared.

"Well...this isn't good..." Ritsuka said as he was baffled with what he just saw."

"Yeah. I guess it's safe to say that Shirou-san is now missing because of what we just saw," Mashu replied in agreement.

"Well then, that explains why you two weren't able to see him earlier...he was suddenly teleported somewhere..." Da Vinci said in disbelief at what she just saw. "And furthermore, what was that envelope? I've never seen that before."

"Me neither. Mashu, have you seen that envelope before?"

"N-No. I have never seen that envelope before senpai," Mashu replied.

"I see...so, what do we do in this case?" Ritsuka asked.

All three of them were silent before Da Vinci said her answer.

"Well...we're going to have to tell them..."

Ritsuka and Mashu sighed in unison at Da Vinci's idea. "I've got a bad feeling about this..."

News about Shirou's disappearance were spread in Chaldea, and the results were...chaotic. Just as Ritsuka and Mashu expected.

Because, upon hearing the news of Shirou's disappearance, Arturia and her counterparts went crazy and ordered the Knights of the Round and both Merlins to find Shirou and bring him back here, in which they eagerly agreed. Not only that, but Ishtar and her counterparts, Parvati, Kama, BB and her sisters, Illya and her counterparts, Miyu, Astraea, Irisviel, Jaguar-man, and surprisingly Kiritsugu, EMIYA and his altered counterpart, Nero and her counterparts, Jeanne D'Arc Alter and her santa lily counterpart, Okita and her counterpart, Musashi, Lancer Cu, and Medusa joined the search for Shirou.

And in the process, Chaldea became a giant mess as everyone went to every room, turning them upside down in their search for Shirou.

Right now, a week has passed since Shirou's disappearance and Chaldea was still in chaos. Ritsuka let out a sigh as he was drinking a glass of water in the cafeteria.

"Senpai? Are you all right?" Mashu asked as she sat next to him.

"Y-Yeah. I'm just exhausted now," Ritsuka replied.

"From finding Shirou-san?"

"Exactly. It's been a week since Shirou disappeared from Chaldea, and we have no clue or trace where he is. Right now, Arturia and her counterparts along with the others are searching every singularity Chaldea located now to see if Shirou is in any of them, and Da Vinci is working overtime searching any singularity she can find."

"I see..."

For a moment, Ritsuka and Mashu were silent before a few more people came into the cafeteria.

Which happened to be Arturia, Ishtar, Parvati, Astraea, Irisviel, Jaguar-man, Kiritsugu, and EMIYA.

"Hey there everyone. Any luck on finding Shirou?" Ritsuka asked.

Everyone shook their heads sideways in response.

"I see..." Ritsuka said with a sigh. Everyone then sat down in defeat. "Damn it, we still can't find a clue where Shirou has gone to...man, I wish that Shirou would appear out of nowhere right now!" Ritsuka thought.

However, at that moment, a portal suddenly appeared in front of them, shocking everyone and making them nearly jump out of their seats. For a second, nobody did anything as they were wondering where the portal came out of and were thinking what the next course of action should be.

But they didn't have to.

Because it was then that a figure came out of the portal.

And that figure was Shirou, who looked tired and beaten up.

"SHIROU?!" Arturia, Jaguar-man, Irisviel, and Ritsuka yelled.

"EMIYA-KUN?!" Ishtar yelled.

"SENPAI?!" Parvati yelled.

"ONII-CHAN?!" Illya yelled

"SHEROU?!" Astraea yelled.

"Shirou-san?!" Mashu said.

"What the hell?!" Kiritsugu and EMIYA yelled.

"Hey there...everyone..." Shirou muttered before he passed out and fell to the ground immediately, causing everyone to head towards to where Shirou was in worry.

"Quick! Someone better take him to Nightingale's office!" Ritsuka yelled.

"I'll do it!" Arturia replied.

"Good! Take him there! Quickly!"

Arturia then gently picked up Shirou and carried him to Nightingale's office...in bridal style, making Ishtar, Parvati, Illya, and Astraea slightly jealous on the side. While everyone else was relieved that Shirou finally returned to Chaldea, he had so many questions that needed to be answered.

After a few minutes, Arturia returned to the cafeteria with relief on her face. "Shirou's going to be fine. Nightingale said that he'll be okay when he gets some sleep."

Everyone let out a sigh of relief upon hearing the news. "Phew. Well, I'm glad that's over," Ishtar said.

"Yeah. Although where was senpai all this time?" Parvati said.

"Yeah. We couldn't find him for a week and suddenly, he appears out of a portal," Illya said.

"I know right? Where did that come from?" Astraea asked.

"I don't know, and I don't care. Shirou's back, and that's that," Jaguar-man said.

"Right. Although he will have a bunch of questions to explain later..." Irisviel said.

Kiritusgu and EMIYA nodded in agreement. "Just where did my younger self go for an entire week..." EMIYA thought.

"Well, Senpai, looks like everything will be normal again," Mashu said.

"Yeah. Although it doesn't explain where Shirou was during this entire week. And the envelope...what was that?" Ritsuka said.

However, it was then that a servant suddenly barged into the room. "Master!" the servant said.

Ritsuka turned around to see Tomoe Gozen, who was panting from the running she had to do. "Oh, hey there Tomoe. What seems to be the problem?"

"Master! Look at this!" Tomoe said as she rushed up towards him with her smartphone.

"Hm? What is it?"

"Remember the Fire Emblem game that was released a while ago?"

"You mean Fire Emblem Warriors? Yeah. Why?"

"Well...a new DLC has been released, and when I checked what it was going to be, you won't believe what I saw."

"What?"

"This!" Tomoe yelled as she showed Ritsuka what she was talking about. As she did, Ritsuka dropped his jaw at the news Tomoe was showing him.

"You...you got to be kidding me..." Ritsuka muttered in disbelief.

"Hm? What is it senpai?" Mashu asked.

"Well...look at this..."

Mashu then looked at the smartphone and in an instant, her jaw dropped too. "Is this...is this even possible?!" she exclaimed in disbelief.

"Somehow it is...and I don't even know how..."

"What are you looking at master?" Arturia asked.

"This," Ritsuka said as he handed the smartphone to Arturia and the others. As they looked at it, they were in disbelief at the piece of the news they were looking at.

"N-No way..." they all muttered.

Ritsuka let out a sigh. "Yes. Apparently, Shirou is in Fire Emblem Warriors as a DLC character, along with a quest of his own. That's the reason why we couldn't find him for a week. He was stuck in there."

For a moment, everyone was silent upon hearing Ritsuka's words. Then the entirety of the cafeteria went into chaos.

"HE WAS IN ANOTHER WORLD FOR AN ENTIRE WEEK?! AND HE MANAGED TO BE IN A VIDEO GAME AT THE SAME TIME?!" they all yelled in unison.

And just like that, Ritsuka found out that the world of Fire Emblem is real...and Shirou had the privilege to live in it for a bit.

After Shirou recovered, he answered a lot of questions which involved him telling how he was teleported there, how he fought armies, and how he was sent back to Chaldea.

And when the news were spread about his traveling to another world along with him being in a video game, the results...were mixed.

Arturia told her counterparts the news and they were relieved that he returned safely while shocked over the fact that Shirou somehow was teleported to another world and be in a video game at the same time.

Ishtar told her counterparts the news and they were both relieved that Shirou returned, although Rider Ishtar was a little jealous that she wasn't in a video game.

Parvati told Kama, BB, and her sisters the news and they were relieved. Although Kama didn't care about the video game situation while BB and her sisters were jealous that Shirou got to be in a video game.

Illya told Kuro, Sitonai, and Miyu told the news and they were glad that he returned and were in wonder over how he was in a video game. Later, they asked Tomoe if they can play Fire Emblem Warriors as well.

EMIYA told EMIYA Alter the news and he was shocked that his younger counterpart somehow managed to get teleported to another world while getting into a video game at the same time.

Astraea, Jaguar-man, and Irisviel later asked Tomoe to play the game later...just to see Shirou in the game.

Lancer Cu was surprised at Shirou's traveling to another world, the video game, and wanted to know if he can come along the next time something like that happened...along with his counterparts as well.

Medusa was relieved, although she later asked what world Fire Emblem Heroes was.

Upon hearing that the universe Shirou went to had magecraft she didn't hear of; Medea was interested in traveling to that same world.

Hercules didn't care.

Archer Gilgamesh on the other hand...was pissed over the fact that Shirou got himself into a video game before him.

Nero and her counterparts were excited at the new world Shirou explored and the video game he was in.

Jeanne D'Arc Alter said she didn't care...but later, she bought the DLC on her copy of the game on her Nintendo Switch and played it...while not letting Jeanne D'Arc and Jeanne D'Arc Alter Santa Lily find out.

Okita Alter and Musashi were interested in the world Shirou explored and were questioning him while Okita just watched with a sigh on her face.

The Knights of the Round were relieved that their queen has returned...and wanted to know what battles Shirou has got himself into.

Merlin and Proto-Merlin were laughing at the news and asked Tomoe to play the game later.

Waver...was completely dumbfounded over the fact that one of his students managed to teleport to another world...and be in a video game at the same time.

Hakuno nearly flinched upon hearing that Shirou was in a video game.

Sieg was confused and clueless because he had no clue what a video game is.

Arthur was surprised that Shirou did the same thing he did, which was traveling to another universe.

Scathach and her counterpart were amused over the fact that Shirou discovered a world they never heard of before.

Amakusa Shirou, on the other hand, was amused with how Shirou got into a video game.

Jack, Nursery, Paul, and Abigail wanted to play the video game Shirou was in.

Da Vinci was laughing over the fact that Shirou somehow managed to be in a video game...and was even more surprised at how Nintendo managed to come up with that idea.

All and all, things were both normal and crazy after Shirou's return. However, there was one question that still remained.

Who sent that envelope? And how did it appear in Chaldea?

Author's note: And just like that, I've altered Fire Emblem Warriors...well, in Ritsuka's world that is. Also, I do not own Fire Emblem Warriors. Nintendo does.