Buster thinks he has seen UFOs, but Arthur, Fern, and Brain do not believe him. Buster borrows Muffy's telescope and finds a comet headed for Earth. Nobody believes him again, but when Brain confirms it, everyone starts to panic, until Fern notices a piece is missing on the telescope, and it alters the telescope's findings, showing the comet has no chance of hitting Earth. A new family, the Molinas, move in next to the Reads after their neighbor, Mr. Sipple, moves away. The Molinas have two children, Alberto and Vicita. Arthur is worried that Alberto will be mean to him, while D.W. gets frustrated that Vicita wins at every game they play. They both find common ground with their new neighbors when they realize they share many common interests.