There was no jewelry. No treasure map, either. The only thing inside the secret compartment was . . . another key. Another silver key, although this one was bigger and fancier.

Nancy couldn’t help feeling let down, although she said to Bree, “It must be important if somebody bothered hiding it in a secret compartment.”

“Maybe something in one of the other drawers explains what it’s for.”

But the other drawers were all empty, which really didn’t surprise Nancy. After she put the key back in the secret compartment, she turned to Bree. “So? Want to help me paint?”

Of course Bree did. Besides sleuthing, she and Nancy both loved to do interior decorating. That was the professional term for making your room look prettier.

“Nice job, girls!” her mom said when they were finished applying the alabaster paint.

“With the gold, it’s going to look so elegant,” Bree said.

“Better wait for the white paint to dry,” Nancy’s mom advised.

While she was pulling off her smock, Nancy heard someone shouting to them.

“Hey! What are you guys doing?”

It was Grace. Nancy resisted the urge to look at Bree and make a face.

Grace pulled down the kickstand on her bike, a bike that was made in France and cost a fortune, according to Grace. She already had her helmet off and was walking over to the garage.

“It’s my new desk. We’re painting it.”

“It doesn’t look new. It looks old.”

“It’s new to me,” Nancy told Grace. “And it’s practically an antique.”

“It has a secret compartment with a key!” Bree added.

Nancy had wanted to deliver that exciting bit of news herself. Still, it was very satisfying to hear Grace whistle and say, “No kidding!”

Proudly Nancy pointed at the special drawer that was drying on newspaper. “Don’t touch it. The paint’s wet. But you can see the little door inside.”

Grace bent down and whistled again. “So what was inside?”

“Another key,” Nancy said.

“What does it open?”

“We haven’t got a clue,” Nancy admitted.

“Where’d you get the desk?”

After Grace heard about the tag sale, she said, “So, duh! Just go back there and ask whoever used to own the desk what the key is for.”

Nancy and Bree turned to each other and scowled. Grace was right. Why hadn’t they thought of that themselves? That worried Nancy. Maybe because it had been so long since their last mystery, their sleuthing skills were getting rusty!