Spy Camp

Spy Camp: Spy School, Book 2 by Stuart Gibbs

There is no summer vacation for Spy School. Instead, students must go to "camp" where they are trained. Alas, our protagonist's friend finds a secret note for the protagonist asking him to be an agent for the bad guys (Spider). There is an explosion while they are on a bus trip. A girl, who is a super-spy friend of the protagonist and her bumbling dad help to protect them. However, with explosions and hostages, they are not able to make much progress. Eventually the girl's grandpa swoops in to help. Eventually, they discover that a bad guy really isn't in jail and the bad guys have seriously infiltrated the intelligence apparatus. They have some battle within a civil war reenactment and manage to prevent a missle attack by pulling out the plug. The boy ends up realizing that there is advantage in taking credit for things. It all feels like the typically bumbling spy book.