After three months and ten worlds of searching for Wade and Rembrandt, Quinn and Maggie finally reach Earth Prime, only to find it under Kromagg control. Quinn and Maggie manage to rescue Rembrandt from a Kromagg prison, but Quinn is captured and learns the shocking truth about his family.

The Sliders slide into a Kromagg weapons-testing area and Maggie saves the life of the Kromagg commander, Kromanus. While Maggie tries to get the timer back from him, Quinn and Rembrandt discover a Kromagg weapon designed to eradicate humans.

After landing in a San Francisco completely devoid of people, the Sliders go to Quinn's house and discover Quinn's double accidentally slid everyone to a parallel world a few years ago. Both Quinns, Maggie and Rembrandt travel to the world where everyone was sent and rush to set things right.

The Sliders arrive on a world where clones are harvested for spare body parts. Quinn's double is blinded in a lab accident and when Quinn tries to help, he is mistaken for a clone. Meanwhile, the others inadvertently rescue the clone, which Colin tries to teach the importance of family and sacrifice.

The Sliders arrive on a small island, with a very sick Maggie in tow. While looking for help, Rembrandt, Mallory and Diana meet the monks of a secluded monastery. Reluctantly, the monks allow them to stay and give Maggie medical attention. But the Sliders soon learn the monks have a secret and won't allow them to leave.