Mark Neslon, the Interstellar Warrior, and two of his friends, Princess Kathryn and Miranda Patel, travel into the far future to help members of the Human Race escape from tyranny and oppression. The humans, whose level of development is roughly that of the early 19th Century on Earth, have been invaded and enslaved by a spacefaring alien race called the D'aark. Mark has to organise and lead the human armies, who are armed with rifles and cannon and are riding horses, in a way that enables them to overthrow their enemies, who are armed with energy weapons and spacecraft. This difficult task is made easier by his close friendship with a high-born D'aark female and more difficult by all three friends losing their memories on arrival on the human's planet. Kathryn and Miranda decide that they cannot stand the rough soldier that Mark becomes, though they also find it difficult to stop thinking about him, as he does about them.