Separated from his father and their allies at the very moment of their victory, Shirou Emiya is sent fleeing through the mountains of Germany, constantly perused by their enemy's. In an attempt to find a place to hide and recuperate, the young magus uncovers something far older, and far greater, than anything he has before encountered.

【中文注意】UNDERTALE与型月世界（Fate主）的混合同人，包含NE（详写）、GE（略写）、PE（略写）三条线，正文全员向无官配外的cp，番外可能会有cp向也可能没有，看反响，可能考虑在评论区开投票之类的。Fate方面的设定以mooncell系为主，灵感大多数来自FELE、FA和FHA，也有FKL和FGO等系列的设定，为配合UT剧情有少量魔改。UT方面为配合月世界设定改动少许剧情顺序和人物动机，但原作人物关系能保留的尽量保留。另外Frisk等人类对应角色的年龄都有提高，福猹两人惯例使用"她"，主要的怪物对应角色由于各种各样的原因（主要是个人爱好）全员拟人，少量龙套设定为AI、NPC和敌性程序（Enemy）。角色设定属于原作，OOC属于我。基本就是这样了，希望不会被喷。统一搬运存档。

Change one thing, and you change everything. That's the basis for what is called chaos theory or the butterfly effect, and if something as small as a butterfly flapping its wings can change the world, then what would happen if Emiya Shirou's childhood was spent living on the run from Magi before the boy found his way into the Underground? Interesting is at least a given.

An amnesiac ten year old Magus in training Emiya Shirou finds himself the eight human being to ever enter the Underground. With his past lost to him, the young Magus sets out on a journey where he and his ideals will be tested. One thing is certain, no matter what he is fighting for, he has to stay determined. This is the tale of a Sword lost in the Underground. AU. Slow updates.

The boy keep running through blazing city of Fuyuki. Never noticed where he go. Never noticed the surrounding. Never noticed the hole he fall into. That was the beginning story of Shirou. Or Comic Shirou. Or Shirou Doremura. Or i don't know, Just read it. Just One-shot.

Shirou's only dream was to save everyone. To be a Hero of Justice. His fight against Archer had forced him to accept he can't, but Shirou never gave up trying to save as many people as he could. What happens when he falls into a world where he could fulfill his dream? Is he be too distorted to see it?