Book 1 of 5 in the Fiona Figg & Kittly Lane Mystery series.
"1917. New York. Notorious spy, Fredrick Fredricks, has invited Fiona to Carnegie Hall to hear a famous soprano. It’s an opportunity the War Office can’t turn down. Fiona and Clifford are soon on their way, but not before Fiona is saddled with chaperon duties for Captain Hall’s niece. Is Fiona a spy or a glorified babysitter? From the minute Fiona meets the soprano aboard the RMS Adriatic it’s treble on the high C’s. Fiona sees something—or someone—thrown overboard, and then she overhears a chemist plotting in German with one of her own countrymen! And the trouble doesn’t stop when they disembark. Soon Fiona is doing time with a group of suffragettes and investigating America’s most impressive inventor Thomas Edison.
When her number one suspect turns up dead at the opera and Fredrick Fredricks is caught red-handed, it looks like it’s finally curtains for the notorious spy."