Mad Kings of Mars by Rob Dorsey is another mesmerizing, well-crafted entry in The Barsoom Pentalogy series. In this fourth entry, the courageous Prince Darus of the Heliumite Empire and his wife, Princess Zurah, are almost getting comfortable with their life, loving each other, when disturbing news arrives -- Zurah's brother, Teyos Than, heir to the title of Jeddak (king) of Zodanga lives. He has been brought back to life from death through an arcane technology handed down through the Barsoom ancestry. As much as the Prince wants this news to be false, it is true, unfortunately, and the first act of ruthlessness Teyos commits is in sending a bomb that strikes Helium, destroying the Royal Palace of Darus's great-grandfather. Riding a frigate warship, Teyos is determined to unite the other Jeddaks against Helium --and they are convinced of his might and the incredible power of his technology. Helium, the beautiful pearl of Mars, could go down if Teyos is not stopped, but can Darus and the finest of his warriors halt an invasion of this magnitude?