Peppa and Rebecca Rabbit would love to be mermaids! When they come up with a plan to have an under-the-sea party, Peppa gets carried away and invites all her friends over for a swimming disco with starfish-shaped sandwiches and a real beach. There's just one problem ... Mummy and Daddy Pig aren't prepared for this at all! Can Miss Rabbit, Emergency Party Planner and Entertainer Extraordinaire, come to the rescue?