There was someone in the house. Home alone with her young children during a blizzard, a mother tucks her son back into bed in the middle of the night. Then she hears a noise - old houses are always making some kind of noise. But this sound is disturbingly familiar: it's the tread of footsteps, unusually heavy and slow, coming up the stairs. In that split second, she has three choices. Should she hide? Should she run? Or should she fight?