A variety of religious cults have popped up for those wishing to live a different existence than what the corporate communities and gangs provide. The Gardeners is one such cult with strict ideas on how to live in order to return to the ways of Adam and Eve in the Garden of Eden. They want to return to a simpler way of living without genetically engineered food and mass-produced materialistic possessions. They live on the fringe of society using abandoned space to grow their own food and squat in to survive.
In particular, we follow the lives of Ren and Toby - two female Gardeners who grow up before a waterless flood of disease cascades over the world decimating the human race. By luck, they both survive and coincidentally come together to find a new start in a changed world. Both have sordid experiences in their histories before the flood occurs making them strong enough to survive the aftermath of the flood. Their stories are shared as the narrative jumps from the present to flashbacks, catching up eventually to our characters' present.
No detail is overlooks as Atwood shares this potential era in human history. You know these characters like old friends, could walk the streets of these communities with familiarity. This complete picture makes the story so engaging and almost terrifying to "watch" these people struggle in a world so unlike ours today yet not outside the realistic realm of possibilities for our future. In true Atwood style, the world we live in has been worn away by time but remnants of it appear as we're taken through this imagined future.
Through death, disease, heartbreak, and terror, humanity survives. Life as they know it changes dramatically with a future that isn't entirely clear, but there is hope left after the waterless flood washes over the world, punishing it for its indulgences.