"All is Krynoid, all will be Krynoid..." On an isolated Yorkshire hill farm, a strange species of plant has been discovered. Between the stalks of wheat and through the ancient hedgerows, an alien horror is silently choking the land. Eve Black, a young biologist working for the Ministry of Agriculture, is called to the farm to investigate. Instead of finding a simple case of weed infestation, her enquiries uncover a sentient, hostile life form, one intent on destroying every living thing on Earth. The harvest is beginning and the human race is the crop.