Last Night on Union Station — E.M. Foner

Book #16 of the EarthCent Ambassador series. Start the series with the first book, Date Night on Union Station.
 
Rumors are rife on Union Station and the EarthCent Ambassador finds herself defending the Stryx against the suspicions of the advanced species. Dorothy returns to SBJ Fashions from maternity leave and immediately starts spending money while giving Baa an excuse to engage in magic. Samuel and Vivian, along with some old friends, decide to participate in the Open University's cooperative education program with confusing results.