The crown of fire

"The secret network of the great astronomer's spies is the target of an assassination plot, led by the despicable Galina Krause. And now the Kaplans are more alone than ever before as they race from France to Antarctica against a deadly ticking clock. There is not much time left for Wade, Darrell, Lily, and Becca to find the remaining relics and defeat their enemies. But are they willing to risk the life of one of their own in order to save the world?"--Amazon.com.