Teen special agents James and Lauren travel to the US in the tenth book of the CHERUB series, which Rick Riordan says has plenty of action.
CHERUB agents are highly trained, extremely talented and all under the age of seventeen. For official purposes, these agents do not exist. They are sent out on missions to spy on terrorists, hack into crucial documents, and gather intel on global threats all without gadgets or weapons. It is an extremely dangerous job, but these agents have one crucial advantage: Adults never suspect that teens are spying on them.
In "The General," James and Lauren travel to America to help train the army. And while they re there, they get into a little trouble in Las Vegas. What happens in Vegas, stays in Vegas right?"