Becca Sawyer left the cellar, so Nancy returned to the mystery. The hidden passageway which was part of the school furnace was now opened, so Nancy crawled through the dirty grate in order to reach the hidden room.
Nancy's heart flooded with anticipation, because she knew this was the end of her adventure. At the other end of the short tunnel, Nancy would find the Black Cat, the culprit who had been attacking all the girls at Waverly. Nancy pushed and pulled herself out of the end of the tunnel, then stood up.
In front of Nancy was something that looked like a stone altar. A rough-looking book was on top of the altar, and standing behind it was Corine Meyers, Nancy's roommate.
"Becca!" Corine said, jumping backwards a bit. "What are you doing here?"
"Catching you red-handed," Nancy said. "The entire Black Cat scheme was just a distraction, so you could get your hands on—what is that, anyway?"
"What do you think?" Corine asked. "It's Rita Hallowell's treasure: a collection of Edgar Allen Poe's unpublished manuscripts. Before he died, he gave all his unfinished works to her. I've been looking for this for two months now."
"How did you know it was here?" Nancy asked. "I'm the one with Rita Hallowell's journal."
"She had a journal?" Corine asked.
"Yeah, it's filled with clues and puzzles that led me to this room," Nancy said.
Corine looked upset. "Darn," she said. "If I knew there was a journal from the beginning, that would have made things simpler. All I knew was that Rita Hallowell hid her treasure somewhere in the building."
"So you stole the blueprints and searched the dorm room by room," Nancy guessed. "That's how you found out about Rachel's twin sister in the attic."
"Oh, you're good," Corine said. "You've been in school for three days, and in that time, you've found out what took me months to learn."
"There's a reason I'm a valedictorian candidate," Nancy said. "It's not just because I'm an undercover detective."
"You're a detective?" Corine asked.
"Oops," Nancy said.
"They hired a detective to catch me?" Corine asked, sounding impressed. "I didn't think the headmistress took me that seriously. But if that's true, Becca, I guess we have a standoff here. You can't let me get away, and I can't let you get away."
"It's over, Corine," Nancy said. "Just give up quietly."
"Too bad for you, I've got an ace up my sleeve," Corine said. "I've had plenty of time to examine this room and find the deadly trap that Rita left behind."
"The...deadly trap?" Nancy asked.
"Yoink!" Corine said, as she grabbed the book, accidentally-on-purpose set off the trip-stone, then escaped through the back entrance before it shut.