Sisters from Guangzhou

Exploration Stage: Crystals
From: Inspector
Description: To understand how Angela learned about the people in the city, we need to suspect the people who are the archetypes of the characters in the novel as informants. Surely there are clues hidden in the sketches Angela left behind. Would you mind taking the sketch with the lucky charm on it?
Completed: This is a celestial amulet that's said to bring good luck. It's from a novel called "Sisters from Guangzhou City," in which I helped twin sisters trying to figure out a family secret. This clue points to, yes...Mei and Yuy.