You almost fooled me, y'know.

No, she totally did, right?

It doesn't exist, so it can't be from the Outside? Quite the opposite.

Oh, you caught me?

Indeed. The cause of this incident...

was Gensokyo's nature itself.

Its very system of things that become diluted on the Outside being pulled into the inside.

Yeah, which means...

She came in the same way as the rubbish at Kourindou

or Kosuzu-chan's imported books for instance.

I realized that something foul had slipped into the Village.