Two humans, Olds and Fielder, travel from the year 5477 to find a planet other than Earth in the past, which turns out to be the giants' planet. They show up at the Earthlings' camp just as a giant stumbles upon the Spindrift, but the futuristic humans kill the intruder and disintegrate the body with an amulet weapon before anyone realizes what happened. Steve quickly becomes suspicious of their new guests and learns they are renegades who originally planned to kill all humans on Earth and leaving those few they captured to repopulate the future Earth with humans they can easily control.