Cross My Heart by Carmen Reid

Brussels, 1940. Fifteen-year-old Nicole watches as the Nazis invade Belgium.

Determined not to stand by as her country is brought to its knees, Nicole vows to fight back and joins the Belgian Resistance. Under her new alias - Coco - Nicole embarks on a dangerous new life as a spy, where the only question is not if you'll be caught, but when...

A great book for young adult readers.