By the time you know who (or what) characters the protagonist in Grass finds good, you're already well into Wonderland.
As with all of Tepper's novels, there is also a frontal attack on a recurring question (in case you don't have philosophical indigestion already): What is a worthwhile life? Can it be deferred for "heaven"? Can it be lived without the non-human other?
Marjorie Westriding is a "small being" faced with these questions on the planet Grass, where every plant is a variant of grass, and an evil intelligence lurks in the forest of blades. Her Catholic family and the prevalent humanist religion are both under attack by a widespread plague that has struck mankind everywhere—except on Grass. The monoculture of grass echoes the monoculture of humankind, which has reduced most other species of animals to a sterile gene-sample library. Will Marjorie solve the problem and find the answer to the deeper questions? Will she choose to act?
I always feel as if this is the first Tepper novel I read (actually it was After Long Silence, sadly, not available for Kindle), because it was the first that resonated with my life. The day I opened the book the first time, Iraq invaded Kuwait. Marjorie's dilemma was being played out on the Gulf sands. When the US decided to go into Afghanistan, I reread Grass, and the resonance was still there.
And as we choose today how we will deal with enemies foreign and domestic, the core questions Tepper raises in this novel continue to resonate. We must oppose evil in the world, and we must do it without embracing evil. Otherwise...
Well, all flesh is grass, and there will come a reaping.