The novel on which the famous silent movie starring Rudolf Valentino was based. The plot is set in motion as Lady Conway disapproves of Diana's planning a desert trip with just her Arab guides to accompany her. Diana gets kidnapped by the Sheik, Ahmed Ben Hassan. Finally allowed to ride in the desert alone, she plans an escape. However, the Sheik recaptures her. And so the story unfolds.

It was the 34th century and all five of the Federation of Planets around Sol were buzzing with their usual activity when the Raiders appeared. They were indeed Raiders of Universes because they had ravaged many systems before reaching Earth and showed no signs of slowing down in the least. Their weapons were invincible, their greed merciless and their natures completely alien. Indeed 'they' were from another dimension entirely. Eating up entire solar systems and planets, they slowed down just a bit when intelligent life was found on Earth...