On a hot summer day, the Backyard Gang is so excited to go to the beach tomorrow, but they could not go there because their dad has to go to work. Disappointed, no one knows what to do until Barney comes to life. By using their imaginations, Barney transports the kids to the beach in a flying swimming pool where they build sandcastles, collect seashells, eat peanut butter and jelly sandwiches for a picnic lunch, explore an old pirate ship, go under the sea and meet Barney’s friend, Molly the Mermaid.