AFTER everyone had a turn to pet Isadora the iguana, Mr. Williams put her back in her cage and said good-bye.

The rest of the morning we did independent reading and practiced our spelling words. Finally, at lunch, I sat down with Sophia and Javier in the cafeteria. Shakira and Lizzie sat with us, too.

“Emma, I saw your report last night. I can’t believe Sophia’s costume is gone!” said Shakira.

Sophia just sulked.

“I know, but I’m making progress on the case,” I said, then added, turning to Sophia, “We’re gonna find the costume. I promise.”

“Forget it, Emma. It’s no use.” Sophia sighed. “I’ve decided not to go to the Halloween Festival anyway.”

“But you love Halloween!” cried Lizzie.

“Yeah, don’t give up now,” encouraged Javier. “I know Emma will figure out what happened. Right, Emma?”

“Well … I’m trying. And I have a new clue.” I told them about what Adrian said in class this morning.

“Oh, yeah,” said Javier. “I remember Adrian knocking on my box. I didn’t care, but Ayana sure did. She’s always pushing Adrian around and arguing with him one minute, and then asking him to play at recess the next minute. Girls are weird.”

“See that!” said Lizzie. “We just have to figure out who picked the costume up after Adrian pushed it on the floor.”

“That’s right,” I agreed. Then I opened my backpack to get my purple reporter pad and shiny feather pencil so I could write down the latest clue. When I reached into the side pocket of my backpack, I felt a piece of paper. That was odd. I didn’t put a piece of paper in there. I pulled everything out. And there it was. Next to my reporter pad was a note.

“Guys, look at this!” I showed them.

“Read it!” demanded Lizzie.

I read the note out loud. Here’s what it said:

I know what happened to the Lion costume. Someone took it. Check Sophia’s desk in Miss Thompson’s class.

That was it. The person who wrote the note didn’t sign their name. It was an anonymous tip!

Sophia looked up.

“My desk? But I was at my desk this morning. I didn’t see the costume there.”

“Hmm. What does this mean?” I wondered.

“Whoever wrote that note knows what happened,” said Javier. “We have to check Sophia’s desk again. Sophia, maybe you just didn’t see it in there this morning?”

“Javier, it’s my costume. I love it. I know I would’ve seen it if it was in my desk,” insisted Sophia.

“Well, what if it was in your desk,” continued Javier, “but someone covered it with a magic invisible blanket? Yeah … So it was there but it was invisible, so you just couldn’t see it!”

We all rolled our eyes.

“Sure, Javier. Sure,” I said. “Sophia, as soon as lunch is over, let’s ask permission to go to the library instead of recess. But on our way to the library, let’s check your desk one more time. Okay?”

“Okay,” said Sophia nervously.

“Me too. I’m coming, too!” insisted Javier. “I have to see how this invisible blanket really works …”

“Javier! There is no invisible blanket! Come on, Sophia, let’s go ask Geraldine the lunch lady if we can go to the library,” I said.

“Okay, Emma. I’m sure my costume’s not there, but we might as well look. See you later, Lizzie. Bye, Shakira.”

“Bye, guys! Good luck!” they called back.

And off we went to find Geraldine. Javier followed behind.