In this second novel in the series, Tom Swift may believe he has vanquished the beings formerly known as his Space Friends, but he is in for a surprise. He also finds it to be the most favorable time to leave the Earth and set out into deep space. But, first things first, and he must settle matters with the other beings who appear intent on attacking Earth. While infiltrating their ship he happens on two other Earthlings, long prisoners of the reptilian beings. With their help he faces the Supreme Being.