Cody, Abby, and Fig Newton, alongside Abby's best friend Marcella Walker are dropped off to the Newton's grandparents' farm for a whole week during summer break. As Cody believes there's nothing exciting at the farm, Abby and Marcella rub a Barney doll in his face. Cody starts a game of "keep-away" by taking the Barney doll and running off with it. The two go after Cody, who hides the doll in the bathroom. The girls catch up with Cody, who tells them to use their imagination and laughs when he thinks that nothing happened. However, the doll comes to life as Barney the Dinosaur takes the girls to play in the barn. Cody refuses to believe in Barney, and claims that real dinosaurs don't talk. That night, the kids wish upon a star to go on an adventure and do things no kid has done before. The next day, they find a mysterious egg on the farm that Barney says will hatch if it is kept safe until it fully changes color. When the egg gets lost, they go on a musical adventure to find it. It's an adventure for the whole family that finally gives Barney a screen just his size!