Mrs. Roosevelt's Confidante by Susan Elia MacNeal

Maggie Hope is very excited to be accompanying the Prime Minister to Washington D.C., since she's been away for three years. The United States have just joined the war after the bombing of Pearl Harbor, and Churchill's visit will hopefully drum up more support for the war effort. However, Maggie soon finds herself helping Mrs. Roosevelt when her secretary is found dead and later revealed to be murdered. Against the backdrop of the holiday season of 1941, the reader is immersed in the lives of  Maggie and those around her.