In an isolated cabin without technology, a lone woman lives by herself as she has for many years. She's preparing supper and putting her knives in the rack when she hears a high-pitched whining noise on the roof above her, and then something crashes down upon it. Climbing up, she finds a flying saucer, some two years in diameter, sitting on the roof. Strange noises emerge from it and she hesitantly approaches it.
The woman notices a gangway opening on underside of the saucer. Hiding, she sees a small suited figure, some six inches tall, emerge and walk toward her. She kicks it down to the floor below and shuts the hatch. Another figure attacks her, pointing a ray gun at her. She clutches at her wounded shoulder and then knocks it off the roof with a thrown lantern. Climbing downstairs, the woman finds another small ray gun, and notices blisters on her arm and shoulder where the second creature shot her. She wipes at the blisters with hot water and then hears a beeping noise from the next room.
Taking a candle and a large wooden spoon, the woman goes into the next room and tries to find the creature she knocked down earlier. Poking under the furniture, she reaches for the outside door and pulls back the bolt, to reveal the creature outside. She slams the door shut and bolts it, then pokes under the bed but one of the invaders grabs her spoon. In the tug of war, she loses the spoon and knocks over the candle.
Going back to the kitchen, the woman discovers one of her knives is missing. One of the creatures tries to come through the window and she slams the shutters closed. She retreats back to the main room but one creature emerges from beneath the floor and cuts her foot with the knife. She throws the invader away and grabs an axe, but when she reaches for the door knob to her bedroom the invader cuts through a hole in the door, wounding her hand. The woman slams into the room and tries to find the invader, finally realizing it's underneath the sheets. She bundles up the sheets while another invader fires at her from the window. She shoves it out and shutters the windows, then tries to bundle up the other invader as it cuts its way out of the sheets. She pulls the knife free and then slams it repeatedly on the table, then puts it in a box and puts the box in the fire.
The other invader blows a hole in the floor boards and comes in. The woman grabs a larger axe and waits by the hole, but the invader retreats. Climbing up to the roof, she sees the gangplank closiong. She hacks furiously at the saucer, destroying it. As she does, she hears a radio broadcast: the invader notes that his companion has been killed and their vessel destroyed, and the planet is inhabited by a race of giants. She finishes the job but doesn't know what the identifying mark on the side means: "U.S. Air Force: Space Probe No. 1."