Billy Sure Kid Entrepreneur Is a Spy! Billy Sure #6

Billy's mom has always claimed that she is a scientist doing research for the government, but Billy suspected there was more to the story. It turns out he was right–his mom is a spy! And now she has enrolled him in spy school so he can create inventions for her top-secret spy unit. Billy is thrilled, especially because he gets to try out lots of awesome spy gadgets! But when Billy creates a special invention for his mom, the blueprints mysteriously disappear. Who could have taken them? Is there a double agent at spy school? It's up to Billy to find out!