To their great surprise, and without knowing it, it was Mycroft that gave their inquiry the most capital clue. Sherlock older brother had come for a family diner, quite reluctantly (apparently under his mother's threat), and had immediately shown a deep contempt toward Mia. While they were dining, Mycroft gave away an information that immediately provoked a reaction on the two teenagers.
"They've found one of the missing girls." he said.
"What ?" Sherlock reacted. "Are you sure ?"
"Yes I'm sure, stupid little brother. In the forest where she vanished two years ago."
"Alive ?" Mia asked with little hope.
"Negative."
Mrs Holmes sighed.
"Well, at least, she'll be given back to her family."
All during the diner, Sherlock kept frowning. When they left the table, Sherlock took the picture of the girl in his files, and then met Mia in her bedroom.
"Something's wrong..." Sherlock said, nervously tapping the picture. "He's breaking his patent."
"She's been taken two years ago, right ?"
"Do you have something in mind ?"
"Several things. She's the first one we found. Maybe the others are still alive."
"That's a possibility."
"I think he wasn't expecting her to die. But now she's no use to him, he has no reason to keep her."
"No use ?"
"It's the only explanation. He uses the girls for something. When was the first kidnapping ?"
"Four years ago."
"Are you sure ? What if it goes back further than we thought ?"
A moment of silence followed.
"Do you know where she's been found ?" Mia asked.
Sherlock nodded.
"I need you to take me there." she said again. "Soon as possible."
"She's probably not there anymore."
"Doesn't matter. I need to see."
Sherlock stood silent for a moment, and then :
" tonight, midnight."