Caroline is approached by an old college mate Mat with a story that he's writing that involves her great aunt Caro, her grandmother's (Margo) sister. He comes with the story that her great aunt betrayed her family and ran off with her German lover. 

These choices her great aunt made affected her whole family even to Caroline's time. Determined to see what's true, she flees to her family ancestral home in London where she discovers letters and diary entries that tell a different story that she has to chase with clues she gathers from within them. 

I love that most of this was told through these letters and diary entries. It really gives you (and Caroline) a sense of what these twins were really like. I love how all the puzzle pieces fit together and help bind Caroline's family a little more to each other.

I have to admit, the discoverys could have come a bit quicker. The storyline seemed to drag a bit too long in many places.