The Things We Cherished by Pam Jenoff
Charlotte Gold is shocked when her ex-fiancé Brian appears on the doorstep of her law office with a troubling case. Roger Dykmans, a wealthy financier and the brother of a Holocaust hero, has been accused of World War II-era war crimes, including the betrayal of his brother and the Jews he tried to save. All Charlotte needs to do is travel to Munich and help Brian's estranged brother Jack prove Roger's innocence.
Despite her misgivings, Charlotte agrees, but the case is soon hindered by the client himself. Roger refuses to help with his own defense, revealing only that proof of his innocence lies inside an intricate timepiece last seen in Nazi Germany. As Jack and Charlotte track the anniversary clock through the past century, they learn of Roger's love for his brother's Jewish wife, Magda, and the tragic decisions he had to make to save her--all the while fighting a growing attraction of their own.