A woman lives with her seven-year-old daughter and newborn son in an isolated house in the middle of a mournful landscape; it seems as if winter has encased everything in a bluish, glass-like shell. The nervous woman is filled with a sense of dread and fear, which she tries to sate by taking walks in the woods. Her husband doesn't get home till late, the baby is sick, and she worries about his welfare until she is absolutely frantic. Not understanding his wife's problems, her husband suspects her of exaggerating her mental breakdown. He is unwilling to admit that even his daughter's behavior has altered. Something ominous is infiltrating the atmosphere of their home....