In a quiet suburban home at night, a little girl, Tina, cry is crying in her room. Her parents Chris and Ruth hear her and Chris gets up to see what's is bothering her. Their dog Mack is barking at the patio door, but Chris tells him to lay down. He goes to Tina's room and finds her bed empty. He looks under the bed but despite the fact he can hear her crying, she isn't under the bed.
Ruth comes in and starts to panic when it's clear that their daughter has disappeared, despite the fact they can still hear her. Chris calls his neighbor Bill, a physicist, and asks him to cover over, desperately trying to explain what has happened. As he goes back to the bedroom, Chris lets Mack in before his barking wakes up the neighborhood. Mack runs under Tina's bed... and disappears.
Bill arrives and has them move the bed after marking the location of the legs with books. He then goes over every square inch of the floor and wall, and finally finds a spot where his hand simply... disappears into the seemingly solid substance. Bill expains that the only possible explanation is that it's an opening to another dimension. Ruth wants to go in to get Tina but Bill warns that if it were that simple, Mack would have found her. As another fourth dimension, it doesn't correspond to their world. Bill has Ruth get him a piece of chalk and he marks off the borders of the "gap" in dimensions. As he does so, he explains that the two dimensions may reach points of parallel correspondence, and the juncture is a temporary one, a freak of nature. Having defined the borders of the juncture, they realize that they can't hear Tina any more.
Bill has the move around to make noise and Tina eventually starts crying again, seemingly from the ceiling. They search throughout the house and Bill finally tracks her voice to the living room. He concludes that any minor movement she makes could correspond to larger distances in there. Bill has Chris call Mack and Tina finds her pet. Ruth calls out, telling Tina to go with Mack. They go back to the bedroom and Chris calls for Mack to come. Bill warns they can't take the chance of going in but they can hear Tina approaching the juncture but then fading away. Chris reaches into the juncture... and falls through. He finds himself in a distorted landscape of fog and mist, and Bill calls out to say Chris has to stand still and call for Mack to approach. He tells Chris to hurry and Tina's father calls out desperately for Mack to come. Mack pulls Tina by her nightdress and Chris finally sees her. He manages to grab her and Bill pulls them all back out.
Ruth takes Tina out of the room while Bill explains that he was holding onto half of Chris on the third-dimensional side of the juncture. Chris wasn't even aware that Bill was holding him. Bill demonstrates that the juncture was closing and knocks on the now-solid wall. Another few seconds and Chris would have been permanently split between the two worlds.