Wayne is a pilot in Canada who is flying a plane with his young American co-pilot Alex. They land for a layover in a small town in Ontario and set off for the de-icing station so they can take off again. The de-icing station is separate from the rest of the airport, and it is dark. There is no movement from the truck, but the boom is already hoisted and pointed towards the field and the woods. Wayne and Alex see a flash of green through the trees in the woods. Alex explains that it cannot be the Northern Lights, because it is too low and not the right time. He also reveals that some people call the aurora "The Nimble Men." Wayne calls the tower and says that the de-icer is not moving. The man in the tower, Bill, says to sit tight and not move. The communication line closes, and Wayne and Alex see more lights again. Wayne can see the platform jockey on the de-icing truck, but he is hunched and not moving. Alex decides that they should go see what is happening. Wayne and Alex go out into the main cabin, where there are six passengers and an in-flight technician named Jamie. Alex and Wayne tell her they are checking out what is outside. As they open the door, all of the passengers watch them except for one middle-aged man, who has his head against the window and his eyes closed tightly. As they walk down the steps, the middle-aged man gasps. They see more lights, and Jamie thinks it is airport lights reflecting off the ice. Wayne asks about the passenger who seems unwell, and Jamie says that she has seen him crying. Wayne tells Jamie to go inside, and that they will be right back. Outside, there is a flash of light right over the heads of Wayne and Alex. Wayne hears a whining sound in his ears. Wayne and Alex realize the truck is now on, so Alex decides that they should go get it. The man in the cab finally sees them, and he starts waving his hands around and shouting, but they cannot hear him. The sound returns, and Wayne thinks it sounds like teeth gnashing. All of a sudden, the lights all slide out from the forest and group together. Wayne and Alex start sprinting, but Wayne is older and slower. Wayne feels the lights all over him, which makes him ache. Then the de-icer starts pummeling him with fluid. Wayne begins crawling towards the plane, while the gnashing sound gets louder until it feels like it has clamped down on his spine. Alex yanks him inside the plane. They clean up the de-icing fluid, when Jamie comes into the cockpit and reveals that the crying man is gone, but she did not see him leave. Years later, Wayne and Bill, the man who was in the tower, are drinking before they retire from flying. Bill tells Wayne that what happened that night happens very rarely, only in the dead of winter when it is the coldest. The de-icing fluid helps keep the lights and the gnashing back. Bill reveals that the victims are always sad. Wayne wonders if his grief drew them, and thinks that he only survived because they took the crying man instead, whose grief must have been more fresh. Wayne explains that the small airport was shut down, and now only the larger, well-lit airport in the area is in use.