Spy Night on Union Station — E.M. Foner

Start series with the first book, Date Night on Union Station Spy Night on Union Station is is Book 4 of the EarthCent Ambassador series. The story picks up less than a year after the events of High Priest on Union Station, with Kelly coming to the conclusion that EarthCent needs an intelligence service. Of course, EarthCent has no institutional knowledge of what spies do, or how they work, so the new agency gets off to a slow start. Then Kelly and the Union Station crew come up with a brilliant idea.