Ruling from his palace on the idyllic island of Acacia, the emperor of the Known World, has inherited generations of apparent peace and prosperity established ages ago by his ancestors. He's an intelligent man, a widower who dotes on his four children and it is this devotion that obliges him to hide a terrible secret from them: that their prosperity rests on the dark realities of trafficking in drugs and human lives. A man of integrity, he hopes that he might bring an end to this vile trade, but powerful forces stand in his way. And then an assassin strikes, a lone killer sent by the Mein, an ancient enemy of the Acacians, long ago exiled to the frozen north. Now they have returned to take revenge on their old enemy and they begin a series of surprise assaults on Acacia. Mortally wounded, the emperor puts into play a plan that will allow his children to escape, to fulfil his or her own destiny. And so they begin their quest to avenge their father's death and restore the Acacian empire - this time on the basis of universal freedom...