'Zero Hour' presents a chilling narrative centered around a young girl named Mink, who is deeply engrossed in a game called 'Invasion.' The story begins with Mink excitedly gathering various household items to prepare for the game, which she plays with her friend Anna. As Mink describes the game, it becomes clear that it involves a fantastical invasion led by a mysterious figure named Drill, who she claims is not just a child but a Martian. Mrs. Morris, Mink's mother, observes her daughter's enthusiasm with a mix of amusement and concern, especially as Mink reveals that the game involves getting rid of the adults during the invasion. The stakes rise as Mrs. Morris learns that 'zero hour' is set for five o'clock that very day. As Mink and Anna's preparations intensify, Mrs. Morris begins to feel an unsettling sense of dread. She recalls her own childhood and the power of imagination, but she can't shake the feeling that this game is different. The conversation with a friend reveals that children across the country are playing the same game, heightening Mrs. Morris's anxiety. As the hour approaches, strange noises and explosions are heard outside, and Mrs. Morris's fears escalate. She becomes frantic, realizing that the game may not be just innocent play but could have dire consequences. The tension culminates as Mink and her friends, under the influence of Drill, prepare for the invasion, leaving Mrs. Morris and her husband trapped in a terrifying situation. The story builds to a suspenseful climax, leaving the audience on edge as they wonder what will happen when the clock strikes zero.