Touhou Gensou Narratograph: Who Are You?

Touhou Gensou Narratograph: Who Are You?
A star falls into Gensokyo. The next morning, the girls who head into the Forest of Magic to look for it instead find a humanoid figure.
An outsider who has lost her memory, and does not even remember her own identity. To help her, the girls set out to fly around Gensokyo looking for anything that could be a clue.