Arthur's first sleepover is everything it should be: He and his two best friends camp out in the backyard, eat pizza, trade baseball cards, and stay up until all hours. The camp-out also gets an added dose of fun from pranks played on the campers by Arthur's sister, D.W., and the boys' reciprocation. It seems there have been alien sightings in the area and, as much as Arthur protests that he doesn't believe in UFOs, he runs as fast as anyone when he sees flashing lights outside the tent. The culprit is D.W. and her flashlight. Arthur and his friends, in turn, create a frightening green creature out of cardboard to hold up outside of D.W.'s window. She sees it and screams loud enough to wake the house. When Arthur's parents go to check on the boys, they are all sleeping sweetly. Or so the parents think. Yet another diverting adventure from veteran Arthurian Brown (D. W. Rides Again, 1993, etc.).