The Centerville Code — Jan Weeks

A boring summer vacation turns into a hunt for a gang of antiquities thieves when eleven-year-old Zack Harris and his buddies discover a coded message hidden in an old oak tree. Zack rallies Paprika, Stinky and twins Ricky and Randy to help solve the mystery. While examining the slip of paper at the Snack Shoppe, the boys notice Evan Zolotny, a new kid they've ignored because of his shabby appearance and not-so-shabby smarts. Zack decides to use Evan's brains to help in deciphering the message. For Evan, it's a piece of cake.

Evan and Zack become buddies, even though Paprika and the twins still view him with suspicion. As the gang discovers more coded messages, Evan's skills become invaluable.

The museum is broken into, Native American artifacts are stolen, and Zack and Evan connect the mysterious messages with the thefts. The kids take turns staking out the oak tree in the park. “Bushy Beard,” one of the thieves, picks up the message while Evan is on duty, and Evan slips into Bushy Beard's van. After a jolting ride to the river, Evan tries to trail the bad guys but loses them.

Zack goes to the police, but they treat him like a pesky little kid and ignore his information. Another museum robbery leaves a guard seriously injured, and the boys know it's up to them to stop the crooks -- no matter what.