The Morrow Family Saga, Series 1: 1950s, Book 5: Star Baby

Natalia is going through the changes of becoming a teen. She is thirteen and naive where love is concerned. She has not emerged from her fantasy world and it has her parents deeply concerned...especially when she decided to pursue Tobias French, a boy known for his criminal activity. On the other side of the pond, Vietnam is heating up. The French have begun their retreat from French Indochina and the US is now casting its collective gaze toward that little piece of hell.
Behind enemy lines, Demmie and Nick Morrow race against time to map out the enemy's intricate tunnel network before their bosses send forth troops to replace the retreating French.