Nice going!” Sergeant Casey said to the Code Busters, after he and his two officers had taken Ms. Cassatt into custody. “You kids took a very big risk, and you could have gotten seriously hurt, but it was clever of you to dress like a mummy, son, and make all those weird sounds.”

Now that the standoff was over, the kids were back in the museum lobby, talking to the sergeant and Dr. Jordan. Ms. Stad had a protective arm wrapped around M.E. and was listening as the Code Busters explained the details of their plan.

“We figured if we distracted Ms. Cassatt, you might have a chance to get her,” Cody said to the sergeant.

He shook his head. “Yeah, but it could have backfired, you know.”

The kids nodded.

“How did you make your voice sound like a mummy’s?” Dr. Jordan asked.

Quinn explained, “There’s an app for that. It’s called Scary Voice Changer. You can do all kinds of things with your voice—sound like a robot or a mouse or an alien. Or make it sound like you’re underwater. You can even add an echo.”

“The mummy app is awesome,” Luke said, grinning. He had pulled most of the toilet paper off, but a few pieces were still stuck inside his waistband and in his shoes. “Oooawwwww,” he added, demonstrating the mummy sound while wiggling his fingers.

“How did you know she was afraid of mummies?” Ms. Stad asked. She gave M.E. a squeeze.

“We didn’t,” M.E. answered. “But we figured, after she’d spent all these years hanging out with mummies, we might at least startle her.”

“Well, you did that,” the sergeant said. “I especially liked the flashing red light. I suppose you used an app for that, too?”

Cody nodded, then touched the icon on her phone. The room lit up with swirling red light.

“Pretty cool,” Dr. Jordan said. “I might have to add those tricks when I give talks to students. Maybe I’ll even dress up like a mummy and use that mummy voice.”

Ms. Stad arched her eyebrow.

“Then again, maybe not,” he said, grinning sheepishly.

“So, what’s going to happen to Ms. Cassatt?” Quinn asked.

“For now, jail,” the sergeant said. “I’ve got a couple of officers checking out her home. I have a feeling we’ll find more artifacts she might have ‘replaced.’ ”

“Is she a real forger?” Luke asked.

Dr. Jordan shook his head. “I doubt it. That’s quite a skill to master. But she knows a lot of people in the world of artifacts—some reputable, some not. It wouldn’t be difficult for her to find a forger to make the fakes.”

“Then all she’d have to do is switch the real ones with the replicas when no one was around,” Quinn said. “I saw that in a movie once.”

“Yeah,” Luke said. “Then she could sell them on the black market.”

“Or keep them for herself,” M.E. added, “and pretend they were reproductions. I wouldn’t mind having some fake Egyptian jewelry to wear.”

“Can you get those things back from the black market?” Quinn asked.

“Sometimes they turn up,” Dr. Jordan said. “But often they go missing for decades. It’s a good thing you figured out what she was doing; otherwise, it could have been a lot worse.”

“Why did she do it?” Cody asked, shaking her head.

“Who knows why some people become greedy?” Dr. Jordan answered, holding up the recovered Eye of Horus and admiring it. “It’s not always easy being around all these beautiful treasures, knowing you’ll never own them. Mirabel Cassatt loved her jewelry. I suppose she got tired of wearing imitations and wanted the real thing. And working here, she thought she could get away with it.”

“But she tried to make it look like I stole that Eye of Horus!” Cody said.

Dr. Jordan nodded. “She must have dropped it in your pocket at some point, to take the focus off herself.”

Cody remembered when Ms. Cassatt bumped into her, just before she accused her of stealing the artifact. That would have been the perfect opportunity to slip the Eye into her pocket. Sort of like a pickpocket, but in reverse.

“Well, I’m just glad this is over,” Ms. Stad said. “We’re going to be very late getting all the students back to school. Our volunteers are calling the parents so they won’t worry. I just hope we’ll still be allowed to go on more field trips.”

“Me too,” said Quinn. “ ’Cause this one was awesome!” He fist-bumped Luke.

The adults laughed and shook their heads.

Awesome? Cody thought about the close call she’d had with Ms. Cassatt and shivered. If it hadn’t been for her friends, she might have ended up sharing eternal space with that old mummy. Not so awesome. But it was still nice to know she had helped save a bit of priceless history today.

While the adults chatted, Cody turned to her friends and signed,

Code Buster’s Key and Solution found on this page, this page.

Then they all linked their index fingers—Cody to Luke, Luke to M.E., M.E. to Quinn, and Quinn back to Cody—to form a circle. It was the American Sign Language sign for “friendship.”