Ima's long ago boyfriend, Paul Kaminski, goes to Estonia to collaborate with scientists on his artificial heart project. When the equipment disappears, Paul asks Ima to bring a fresh set to continue his research. Concerned about going to a Soviet Republic, Ima invites her Manhattan pal Riina Feingold to come along as interpreter because her parents had fled to New York from Estonia in 1940.
As couriers of scientific equipment, the young ladies head for Tallinn, Estonia. Upon arrival, they get accused of a spy plot. Ima tries to convince Customs that the apparatuses they carry are not bombs. The officials seize their passports and equipment. Then, Riina's last name reminds them of a murderer who escaped in 1942. While Ima gets involved in investigating the whereabouts of the missing artificial hearts, KGB seeks to arrest Riins to use her as a bargaining chip for the return of her father to his native land.
Ima and Riina need more than passports to get out of the trouble they meet. They don't understand the ways of communism. Both work hard to identify friends and foes behind the Iron Curtain. Their adventure is no vacation. In fact, when Riina must hide on the rooftop, it brings shades of The Diary of Anne Frank. This case stretches Ima'skill across the Atlantic. She finds that stolen artificial hearts and bungling ambassadors make strange bedfellows. So laboratories and larceny constantly punctuate her Escapades in Estonia.