I am a movie director and I just received the following movie plot. Could you help me answer this question? If not, let me know by writing "Not answerable". Plot title: Signs Movie plot: Graham Hess (Mel Gibson), a former priest, lives with his asthmatic son, Morgan (Rory Culkin), his daughter Bo (Abigail Breslin) who leaves glasses of water around the house for various reasons, and his younger brother Merrill (Joaquin Phoenix), a failed minor league baseball player, on an isolated farm in Doylestown, Pennsylvania. Hess has lost his faith and gave up his priesthood after his wife, Colleen, died in a traffic accident caused by a town local, Ray Reddy (Shyamalan). One morning, Graham discovers a crop circle in his field. While investigating the crop circle with the local law enforcement, Morgan is forced to kill one of the family dogs when it turns violent against him and Bo. Graham then learns of animals becoming violent across town. They hear reports of crop circles appearing around the globe, and there are reports of strange lights over Mexico. Later, Graham and Merrill find the farm is being watched by a tall dark figure which disappears into the fields when they give chase. The next day, they hear strange noises over a baby monitor, but cannot find their source. Graham approaches the crop circle but on seeing a green leg sticking out of the cornrows, flees back to the house. After opening up to Merrill about the death of his wife, noting that her last words were "tell Merrill to swing away", Graham goes to visit Ray, the first time since the incident. When Graham is gone, Merrill and the children watch a news report about footage taken of an alien creature in Brazil, showing that the aliens can blend into their surroundings. Merrill joins the children in wearing tin foil hats, believing the aliens can read their minds. At Ray's, Graham finds Ray is bleeding from an injury but otherwise apologetic for the accident. After Graham accepts his apology, Ray departs for a nearby lake, saying "they" do not like water. Graham finds Ray has trapped one of the aliens in his pantry, and tries to see what the alien looks like using a kitchen knife under the door; the alien grabs at him, and Graham... My question: what did the family discover as the aliens entered the house?
The answer to this question is:
That they had left the attic door unguarded.