Manhattan is a treasure trove of history and culture; especially in and around Central Park. One can walk, jog, bike or take a tour through the park and see statues, fountains, sculptures, bridges, pavilions, lakes, ponds and even a castle. Near the park is the Metropolitan Museum of Art, the Haydn Planetarium, Carnegie Hall, Lincoln Center, American Museum of Natural History and the Museum of Modern Art, just to name a few centers of culture. Julia Hamilton lives and works in Manhattan and enjoys all of the culture that the Big Apple has to offer. She owns and operates a successful interior design company and accepts an assignment to recreate a retail shop in a residential co-op on 5th Avenue for Mrs. Ellis Wellington. Mrs. Wellington's antique shop in Germany was destroyed during Kristallnacht in 1939. To be authentic, the design must include an indoor fountain. That's when Julia discovers by unusual means what lies beneath the island of Manhattan. While researching her heritage, Julia becomes interested in the life of Per Lundgren, her great uncle who was a Swedish diplomat during the Second World War. She found that he joined forces with Blue Tango, a German underground group in Berlin in 1940; their mission was to save as many people as they could from the Nazis. Julia is compelled to tell her uncle's story, of how he worked with the Blue Tango team and attempted to help French and Polish people escape from Europe. As she comes to know more about the missions, she begins to write a journal. Suddenly, Julia's life in 2015 becomes intertwined with Blue Tango. The journal takes her back in time to Berlin and Stockholm in 1940 and she learns that her uncle was not able to complete his work before being cut down in the prime of his life. Julia's own mission is to finish her uncle's work. She finds that she's on the right trail when she meets a man, seemingly by chance, who is privy to some of the same information that she has written in the journal.