The Viper's Nest

Shaken by a shocking loss, Amy and Dan flee to an exotic land and
trace the footsteps of their most formidable ancestor yet: a military
leader of mythic proportions. But just as the siblings begin
to master the art of ancient warfare, they confront a dangerous
enemy \- the truth. With the stakes higher than ever, Amy and Dan
uncover a devastating secret about the Cahill family that changes
everything.