Billy Sure, kid inventor and CEO of Sure Things, Inc., discovers a big secret about his mom in the sixth book of a hilarious middle grade series! Billy's mom has always claimed she is a scientist doing research for the government, but he's always suspected that there was more to the story. And as 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 all of the awesome spy gadgets and meet three other super smart spy kids. But when Billy is offered a chance to become a spy himself, he has a big decision to make. Does he want to become the world's youngest spy...or is it enough just to be Billy Sure, Kid Entrepreneur?