Kate picked up the notebook. There was nothing inside but a few sheets of blank paper.

“Didn’t you have a copy of them?” she asked. “Or a backup on your computer?”

Kate’s mother slumped into the chair next to the desk. She shook her head. “No!” she said. “I haven’t had a chance to make a copy. And I didn’t record the interviews, either. If I don’t get my notes back, I won’t be able to finish the book!”

“Maybe Mike and I can help find them!” Kate said.

Her mom looked at her and sighed. “Thanks,” she said. “I’d be happy to have your help.” Mrs. Hopkins looked at Emma, the guard. “And yours, too!”

“We are already checking things out,” Emma said. “We reviewed the security video from the hallway and have a suspect. A man went into the press box at three o’clock today. He left a few minutes later, but he wasn’t carrying anything. We don’t know if he was the thief, but we suspect it.”

“Could you see what he looked like from the video?” Mike asked.

“We couldn’t see his face,” Emma said. “But he was wearing a Mets jersey and a Yankees baseball hat.”

Mike and Kate glanced at each other. “Did you hear that?” Kate whispered. “Maybe it’s the same person who left us the note with the hot dogs!”

Mike nodded.

Emma continued. “Milo showed up an hour after the thief was here and noticed some of the reporters’ stuff was moved, so he called us,” she said. “Let me know what you’re missing, Mrs. Hopkins, and we’ll try to find it.”

While Mrs. Hopkins was describing what had been stolen, Kate pointed to the other side of the press box. “Let’s take another look at that note. We can talk over there,” she said. Mike followed her to an empty table.

“It’s probably the same person,” Mike said as they walked. “The timing works out. The thief left the note for us around one o’clock at the Cyclones game. That means he could have made it over here to the stadium by three o’clock to steal your mom’s notes.”

Kate nodded. She dug out the napkin. She and Mike studied the message on it.

Kate pointed to the fifth line. “What about this line: ‘You don’t see me now, but I saw you’?” she asked. “That’s a little creepy!”

“Yeah, but maybe it just means the person who wrote it saw us handing out hot dogs at the Cyclones game,” Mike said. “Besides, whoever it is wants to meet us and your mom, so that’s okay! I’ll bet they want her to pay a big ransom for the stolen notes!”

Kate nodded. “ ‘Meet me at the monuments with your mom,’ ” she read. “What are the monuments? There are lots of important buildings in New York City, like the Empire State Building, but no big monuments like in Washington, D.C.”

Mike thought for a moment. “Look at the next line. ‘When the subways meet a second time,’ ” he said. “I think that means the second game in the Subway Series! The Mets are on the number 7 subway line, and you can reach the Yankees on the number 4, B, or D subway lines. And the second game is at Yankee Stadium tomorrow night!”

“But there aren’t any national monuments at Yankee Stadium!” Kate said. “Where are we supposed to meet him?”

“I don’t know,” Mike said. “Maybe the Statue of Liberty’s a national monument. It could mean that.”

Kate shook her head. “But the Statue of Liberty isn’t near Yankee Stadium. That doesn’t make any sense.”

They both stared at the paper for a couple of minutes. Mike read it over and over to himself. Suddenly, he jumped up and tapped the note.

“Ooh, ooh!” he said. “It doesn’t mean a national monument. Don’t you remember from the last time we were there? It means to meet the thief in Yankee Stadium at Monument Park!”

Kate’s eyes opened wide. “That’s it!” she said. “Monument Park, behind the Yankees’ outfield! That’s where they have all the retired numbers and plaques for important Yankees players and managers.”

Mike nodded. “We meet him there with your mother, and she’ll get her notes back!” he said.

“But the note says only if we turn over something special,” Kate said. “I’ll bet that means a lot of money!”

Mike looked around. The press box was starting to fill up with reporters.

“We should tell your mom,” Mike said. “And then maybe we can get some food and watch the game from up here!”

They headed back to the other side of the press box. Kate’s mom was working at her desk. A few seats over, Milo was typing on his computer. As they approached, Mike held out his hand to stop Kate.

“What’s up?” Kate asked.

“Look over there,” Mike whispered. He pointed to a plastic bag hanging from Milo’s chair. “Maybe we’ve found our thief!”

Poking out of the top of the bag was a Yankees baseball cap!

“It can’t be Milo!” Kate said. “He’s a good friend of my mom’s!”

“But he’s a rival reporter!” Mike said. “Your mom even said that. He probably doesn’t want her to finish the book. He had access to the press box. He has a Yankees hat. He could have faked the robbery and then reported it to security afterward.”

“Okay,” Kate said. “We can tell my mom about the note later. Let’s hang out here to watch the game. That way we can keep an eye on Milo and maybe even find a chance to search his bag for my mom’s notes!”