Sam, Derek, and Caitlin love solving mysteries, and when they visit Washington, DC, spies are lurking. What starts out as a fun game of pretend on the National Mall turns all too real when they follow a mysterious man to a meeting deep within the Capitol. To keep government secrets from falling into the wrong hands, the kids must work with federal agents and travel to historic Mount Vernon for a state dinner with the president and his son. Dead drops, cyphers and spy chases are all part of what might be their most dangerous adventure ever-if it isn't their last"