学校が夏休みに入った翌日。
本来なら長期休暇という解放感に羽を伸ばしていてもおかしくない頃、ラン・シュトラヘルツは機上の人になっていた。義理の姉という事になっている保護者の魔法使い、エルザ・シュトラヘルツが日本へ移住する以前に住んでいた家に向かう為である。
何処までも広がる青い空、ラン達が乗っている飛行機の影が映り込む眼下を流れる白い雲が、高速で後方へと流れていく。
それを眺めるランは、ただ無言。初めて乗る飛行機に興奮するでもなく、見知らぬ地に向かう未知の期待に胸ときめかせている訳でもなく、その胸中を言い表すならば、

どうしてこうなった

の一言に尽きよう。
その原因は、今、ランが置かれている状況によるものだった。
本来であればシュトラヘルツ家にはランとエルザ以外にもう一人、エルザお付きのメイド、ミフィルィナアがいる。通称ミフィと呼ばれる彼女は今現在、突然家出をしたと思えば勝手に日本を出て、海外の知人の家に厄介になっている。それを迎えに行くのが今回の目的なのだが、何故か自分絡みの用事まであるという理由で、強制的にランも連れてこられていた。自分の与り知らない内に、友人達と交わした夏休みの約束をキャンセルせざるを得ない事態に発展したお陰で、前日は終始機嫌が悪かったものだ。ちょっとした事故？で子供の姿になって以降、面白いからとそのままで居続けた義姉が、わざわざ元の姿に戻ってまで誠心誠意謝ってきたのだから、その機嫌の悪さは相当なものだったのだろう。
そして移動手段として、エルザは魔法使いなのだし魔法で一瞬にして移動するのだろうと思っていれば、何故かのんびり空の旅である。一応は可能であるらしいのだが、そういった方法でさえ、数時間、数日ならまだしも、長期滞在する為には正規に入国手続きをしなくてはならない、という規則が国連退魔機関（日本で言う妖怪や能力者達を統括する国連組織）で定められており、国籍を日本に移し帰化しているエルザ達も勿論例外ではない。エルザが伝説に語られるネクロマンサーとはいえ、その正体を隠し敢えて中級魔術師として登録しているとなれば、特例を認めさせようにも無理が生じる。後の面倒事や当地の支部とのイザコザを避ける意味も含め、実はこうした遠回しなやり方が一番楽なのだ、こういうのを日本では【急がば三遍回ってここ掘れワンワン】と言うのだ、とはエルザの言だ。他にも難しい事情を長々と説明されたが理解できず、結局、国境を越えるのだからと言い含められ、渋々納得しておいた。
そしていざ出発という段になって、当日に飛び込みでチケットを取るのでは時間が掛かりそうだ、とゲンナリしていた所、意外にもすんなりと事が運んだ事をやや訝しく思っていたが、驚きはその後にやってきたのだった。
我が物顔のエルザに連れられ向かった先に、小型のジェット機が待っていた。そして、降ろされたタラップの下には複数人のメイド。
その内の一人、エルザに向かい恭しく一礼したコルと名乗る黒髪ショートカットのメイドは、ランに対しても同じように一礼し、自分はシュトラヘルツ家に仕える侍従長だとのたまった。侍従長といえばメイドの中でも一番偉い立場のメイドという事だ。仕えているメイドが指折り数えられる程度の人数、かつ一人で家事全般をこなすオールワークス（所謂下級メイド）であるならば、そんな言い方はしない。つまりシュトラヘルツ家には、少なくとも部署別に担当するメイドが複数名居る事になる。ミフィがいる時点で、メイドが雇えるくらいには裕福なのだろうとは思っていたが、ここまで来ると富豪である。
考えてみれば、隣の古道具屋に住む破天荒な魔法使いにエルザの義妹にされた、それ以前のエルザを知らない事に思い当たり、既にこの時点で背中に嫌な予感が圧し掛かってくるのを感じてはいた。
その嫌な予感に更なる追撃をかけたのが、コルに促され乗り込んだジェット機だ。旅客機、と言われて大多数がまず思い当たるであろうジャンボジェットに比べれば相当な小型機であるとはいえ、この小型ジェット機にはランと、その隣で涼しい顔をしてスコッチを煽る義姉、そして傍らに待機するメイド達以外、乗客は人っ子一人いない。
かといってチャーターしたのかといえば、そうでもないようだった。乗り込む時に見えた機体側面に、誇らしげにペイントされていた「Schtlehertz Konzern」の文字、それが意味するところはシュトラヘルツ家が財閥であるという事、そしてこの小型ジェット機が自家用機である事を示していた。事実、この小型ジェット機を操縦しているのは、パイロットではなく他ならぬコルなのだ。

The day after summer vacation began at the school.
The liberating feeling that comes with a long vacation right in front of her, where she could stretch out her wings. At this normal time, Ran Schtlehertz was boarding a plane. Her wizard guardian and half-sister, Elza Schtlehertz, was heading back to the house that she had lived in before she moved to Japan.
In the expansive blue sky, the white clouds flowing by at high speeds beneath the plane, were reflected in the windows of the plane Ran was in.
Watching them, Ran was silent. She didn't have the excitement associated with flying in a plane for the first time, nor the heart pounding anticipation of heading to an unknown land. If she had to put what she felt in her heart into words,

How did this happen

Was the only phrase to use.
The cause, was due to the circumstances that Ran found herself a part of.
In actuality, the Schtlehertz household consisted of one other person aside from Ran and Elza, Elza's retained maid, Mifilinah. Called Mifi as a nickname, she suddenly ran away from home, and it was thought that she left Japan on her own, and is currently staying with an overseas acquaintance. The current goal is to go and get her back, but somehow, she got caught up in it too, and so Ran was also forced to come along. Along with not know why she's coming, she had to cancel her summer plans with her friends, and due to that, she's been in a bad mood ever since yesterday. 'It's a small incident?' and with that, her half-sister, who had been in child form and continued to stay that way because it was fun, went out of her way to return to her old form to apologize sincerely, so her mood was probably just as bad.
Also, for the method of transportation, Elza, as a wizard, could have instantly teleported with magic, but for some reason, they were leisurely traveling through the sky. That kind of method is possible if it's only a few hours, or a few days, but since this is a long term stay, she has to formally enter the country. These are the rules that the UN demon hunting association (The UN group that regulates what are known as youkai in Japan and people with special abilities) had decided, so Elza, who had become a naturalized Japanese citizen, naturally had to obey. Even as a legendary necromancer, Elza had been hiding her true identity by registering as a mid level magician, so getting an exception would be pointless. To avoid the annoyances afterwards, along with the difficulties over there, using this indirect method is the easiest, and so, according to Elza they say in Japan, "Haste makes a dog dig thrice". The other difficult circumstances would take a long time to explain, and she wouldn't understand, so in the end, since they're crossing borders, she reluctantly understood this was best.
And now on the steps of departure, with the decisive ticket in hand, she thinks that it will take a long time, and so tiredly, and surprisingly unresistingly, she lets herself get carried away, which is somewhat odd, she thought, though that thought only came later.
As she was led by Elza, who was looking like she owned it, she looked ahead, and there was a small jet waiting. At the bottom of the gangway, there were several maids.
One among them turned towards Elza and bowed politely. She called herself Col and was a maid with short black hair. She similarly bowed to Ran, and said that she was the head chamberlain of the Schtlehertz family. As the head chamberlain, she had the highest position amongst the maids. If you could count the number of maids serving them on your fingers or if a single maid could do all of the chores (the lower ranking maid), then she wouldn't have that title. Basically, the Schtlehertz family, at the least has maids in charge of different things and mulitple titles. When Mifi was around, she thought that they were well off enough to hire a maid, but she's actually a millionaire.
Thinking about it, as the half-sister of Elza, a groundbreaking wizard who lived next to an antiques shop, she didn't know anything about Elza before that, and she suddenly felt a bad feeling run up her spine.
That bad feeling increased when Col urged her to get on the jet. Compared to the jumbo jets that most people think about when they hear a passenger plane, this was relatively tiny. There was no other passengers on this tiny jet, except for Ran, and her half-sister, who was stiring a scotch with a relaxed expression, and the maids waiting nearby.
However, this was not a chartered flight. When she was getting on the plane, she saw that the words "Schtlehertz Konzern" was prominently painted on the side. Those words meant the Schtlehertz family was a business conglomerate, and this tiny jet was for their personal use. In reality, the one flying this tiny jet wasn't a pilot, but none other than Col.