A few months ago, Alex's world changed. Forever. Now, just when it seems life is almost getting back to normal, Alex's grandfather crashes back into the picture with grave news: their friend Harry has fallen into the clutches of a familiar foe, and the old man needs Alex's help to rescue him. This time, the duo's desperate dash across Europe leads from Paris deep into Germany's foreboding Black Forest, as they chase down the mystery Harry had been investigating when he disappeared.