The Student Ambassador is back for another adventure, this time heading south on a special mission in Mexico.The first book in the series saw Joseph smoothing diplomatic relations between the fictional East and West Rhutar. Now, on a field trip to the James Olman Presidential Library, he helps his classmates work through a propaganda-ridden simulation exercise. Joseph breaks the rules, goes rogue-and impresses former President Olman. The two team up to get to the bottom of the abandoned silver mines of Zacatecas, Mexico; the trip is also an opportunity for Joseph, whose father is Mexican, to reconnect with his roots. Olman wants to invest in the mines and convince the locals that reopening the tunnels would be for their benefit, as well as his own profit, but spooky masked creatures haunting the mines have kept speculators out. When Joseph discovers who is behind the masked figures and why, he must confront the former president about his misconceptions and persuade the powerful man to listen to the concerns of the disempowered. The storyline has a chaotic start and takes a beat to settle in, but once it does, it's a lighthearted whodunit that encourages readers to think about whose voices they listen to and why. Cartoon images complement the plot, bringing plenty of humor. Olman is light-skinned; Joseph's classmates are diverse.By turns silly and serious, with a satisfying and thoughtful conclusion. (Morse code activity) (Graphic fiction. 7-11)