The Salt Mines Mystery (Thunder and Lightning Series, Book 2)
Threatened in the streets of Goeppingen, Germany, Gabe (13) and Alex (15) Zanadu make a disastrous decision that plummets them, their dogs Thunder and Lightning, and international friends into the clutches of an evil human-trafficking ring. Their vacation collapses in one calamity after another as they must successfully negotiate the Egyptian Path of Death to free themselves, the victims and bring their captors to justice. Another Christian adventure mystery!(276pp. Author, 2015.)
Also available The Secrets of the Castle (Thunder and Lightning Series, Book 1) item #4101.