“I asked which side of the bed you wanted.”

“No. That was yesterday.” I played back what he had just said and that was when I saw it, the pattern I’d been looking for. “You’re brilliant!” I said.

“Thanks!” Tim frowned. “What have I done?”

“Tell me,” I said. “Did Libby come in first in anything at school? And was it . . . by any chance . . . geography?”

“Yes. She did. How did you know?”

“Let’s get back inside,” I said.

*  *  *

I found Eric, Mark, and Brenda in the drawing room. This was one of the most extraordinary rooms in the house—almost like a chapel with a great stained-glass window at one end and a high, vaulted ceiling. Rory McDougal had obviously fancied himself as a musician. There was even a church organ against the wall, the silver pipes looming over us. Like so many of the other rooms, the walls were lined with old weapons. In here they were antique pistols; muskets and flintlocks. All in all, we couldn’t have chosen a worse house to share with a mass murderer. There were more weapons than you’d find in the Tower of London and I just hoped that they weren’t as real as they looked.

The three survivors were sitting in heavy, leather chairs. I stood in front of them with the organ on one side and a row of bookshelves on the other. Everyone was watching me and I felt a bit like Sherlock Holmes at the end of one of his cases, explaining it to the suspects. The only trouble was, this wasn’t the end of the case. I was still certain that I was talking to the murderer. He or she had to be one of the people in the room.

Somewhere outside, a clock chimed the hour. It was nine o’clock. Night had fallen.

“Seven of you were invited to Crocodile Island,” I began. “And I see now that you all have something in common.”

“We went to the same school,” interrupted Tim.

“I know that, Tim. But there’s something else. You all got prizes for coming in first in certain subjects. You’ve already told me that Rory was first in math. Libby was first in geography . . .”

“What’s this got to do with anything?” Eric snapped.

“Don’t you see? Libby was first in geography and someone dropped a globe on her head. Someone told me that Sylvie Binns came in first in chemistry and we think she was poisoned.”

“Janet came in first in French . . .” Mark murmured.

“. . . which would explain why she was stabbed with a model of the Eiffel Tower. And Rory McDougal came in first in math.”

“He was stabbed, too,” Eric said.

“He was more than stabbed. He was divided!”

There was a long silence.

“That’s the reason why Johnny Nadler wasn’t invited to the island,” Brenda said. “He never came first in anything. He was second . . .”