Set on Kudufontein, a remote farm on the border between South Africa and an unnamed country in the 1970s, A Blade of Grass is a charged and complex exploration of apartheid and its consequences. The story centers on Märit Laurens, a young woman of British descent, orphaned and recently married to Ben, whom she joins to live on their newly purchased farm. Not long after their arrival, violence strikes at the heart of Märit's world, leaving her alone and isolated. Devastated, alone, but determined to keep the farm running, Märit turns for companionship and guidance to her young black housekeeper, Tembi, who is in a similar predicament but for different reasons.

Soon Märit finds herself in the middle of a simmering battle between the local Afrikaner community that surrounds her farm and the black workers who live on it, with both vying for control over her land in the wake of tragedy. Facing obstacles of biblical proportions, Tembi and Märit forge a close bond, relying on each other, what's left of their land, and their wits to survive.

Strangers and wanderers insinuate themselves into their sheltered world, including Michael, the mute musician who charms their farmyard animals, and Khoza, a mysterious, sinister figure who upsets the tenuous peace and security Tembi and Märit have found in each other. Perhaps the greatest threat to their world is the encroaching civil war and its soldiers who stir up conflicting loyalties that turn Märit and Tembi's fight for the farm into a struggle for their lives.