Three children, Abby, Marcella, and Cody are visiting at the Newton's grandparents farm. Cody is growing up and disillusioning himself from all the fun little kids stuff like Barney. When Barney comes to life and brings fun and laughter, he starts to fade when Cody doesn't believe anymore. Barney brings the kids to Imagination World, his home where he watches over the world and is reborn when children all over the world use their imagination to make light of their boring lives. Now children are growing up and losing faith in their dreams, which will erase Barney from existence. The group have to reach the darkest place of imagination and make the world believe again.
