"What do you mean you never saw me?" Alex protested. "What about this morning when you bumped into me? You spilled cat food all over the place!"

Korina acted like Alex was a fly who wasn't worth shooing away. "Oh," she said. "Was that you?"

"Yeah, that was me!" Alex said. "And I'd like to know "

But that's as far as Alex got. At that moment Sheriff Marshall stormed through the doorway. His shadow fell over the office, silencing everyone.

"What's the meaning of this ruckus?" roared the sheriff.

Even Deputy Grimaldi looked frightened. He fumbled with his notepad. "Sheriff?" he stammered. "I I was just about to call you. Seems more counterf eit money has turned up."

"Hogwash!" barked the sheriff. "Lucas, this is nothing more than your imagination."

"Maybe," Lucas said. "But this girl agrees with me. There's something fishy about this $20 bill."

"Lucas may be right, Sheriff," said Deputy Grimaldi.

"Hogwash!" repeated Sheriff Marshall. "Them two counterfeiters must be clean out of the state by now."

"Excuse me," said Christopher. "What two counterfeiters?"

"These two," said Deputy Grimaldi. He pulled something from his po cket, unfolded it, and handed it to Christopher.

Alex squeezed in for a look. It was a wanted poster with sketches of two men on it. One man was short and bald with the longest nose Alex had ever seen. The other was tall with long, black hair pulled back into a ponytail. "They should be pretty easy to spot," Alex said.

"Grimaldi!" shouted Sheriff Marshall.

"Sir?" asked the deputy, leaping to attention.

"What's the big idea blabbing official police business to a bunch of kids?"

"I I " Deputy Grimaldi started.

"Now shoo, you kids!" said the sheriff. He handed the money back to Lucas. "Lucas, there's nothing wrong with this money. And that's final!"

The sheriff almost pushed Christopher, Alex, and Korina out the door. It was all Alex could do to stay on his feet.

Outside Lucas' office, Alex turned to pick up where he'd left off in his argument with Korina. "Now then, Korina " he began.

But she wasn't there.

Alex peeked inside the building. He checked outside by the sod a machine. Korina was gone!

"Christopher," Alex said, "where did that girlKorinago?"

But Christopher didn't seem to hear Alex. "Huh?" he said. "Listen, Alex. I've got an idea. I have to check it out. Alone. I've just got to help Tobias. Maybe I'll see you again." Then he was gone too.

Alex stood by himself, the crazy parakeet still on his shoulder. He surveyed the square where shoppers dragged along in the heat. A few boys were throwing a Frisbee at the edge of the park. A huge black dog barke d at them.

So what if Christopher and Korina had taken off! Alex didn't need them anyway. He didn't need anybodynever had. He'd solve Tobias' mystery all by himself.

"Come on, parakeet," Alex said, thinking again that he'd have to come up with a name for the bird sooner or later. "We've got a mystery to solve."

The first thing Alex did was to buy a notebook from Hales Market. He picked a small one with a spiral wire on top. That way he could slide his pencil in the wire and keep it handy. On th e front cover, he wrote: "Alex's Notebook."

Alex flipped the notebook open to the first page. "What should I write?" he asked the parakeet.

The bird cocked his head and squawked, "Mystery!"

Alex laughed, but he wrote "Mysteries" at the top of page one. Under that he listed:

1.Who wrecked Tobias' store?
2.Why?
3.Where are the counterfeiters hiding?
4.Who is Korina?

It would have been nice to have somebody to talk it all over with. Alex studied his list. He liked this notebook business. But where should he start? "I need clues," he said.

"Braawk! Clues!" said the parakeet.

Alex scratched his chin and stared at his list of mysteries. "I don't have a clue who wrecked Tobias' store. Or why. Or where the counterfeiters are," Alex said to no one in particular. "That leaves Korina."

Korina was the key. She was lurking around every corner. Spying.

So Alex formed his plan. He would find Korina and follow her. Somehow she was the link between Tobias' trouble and the counterfeit trouble. Alex was sure. Maybe she was some kind of spy for the counterfeiters. All he had to do was follow herwithout her seeing him.

Alex biked to Tobias' store, the parakeet clinging to the handlebars. He leaned his bike against the red brick wall of Tobias' Ark. Then he ran inside. "Tobias?" he called.

"I'm here," came a voice. Alex spotted Tobias sitting behind his counter. "Is that you, Alex?" Tobias called.

"Hey, Tobias." Alex walked back to Tobias' counter.

Odd-shaped pieces of plain, white paper nearly covered the counter. Each piece had black ink squiggles on it, like parts of letters or words. Tobias tore one last piece in two. Then he began moving the pieces around on the counter.

"What are you doing, Tobias?" asked Alex.

"Nothing much," he answered, lining up the pieces. "I like to make puzzles. See? This goes here. This goes here." He moved each piece until they fit together and formed a solid sheet of paper.

Now Alex could read the words on the paper: "The Lord works in mysterious ways."

"How'd you do that?" Alex asked, amazed at what he'd just seen.

"This?" Tobias said absently. "It comes naturally. I've made little puzzles for so many years, I hardly even know I'm doing it. This one reminds me of the wonderful way God works. Life can look like a puzzle to us sometimes, but God always sees the whole picture and gives us what we need.

"But what can I do for you, Alex?" Tobias asked, reaching out and stroking the parakeet on Alex's shoulder.

"Tobias," Alex said, "do you still have those old costumes from the curiosity shop?"

Tobias scratched his head. "Yes. I think so, Alex. But why?"

"Because I, Alex Ace Detective, need a disguise," Alex said. "I'm about to spy on a spy."