It's a surprise birthday for Cozmo with visits from Leonardo da Vinci, Mozart, Cleopatra, Mr. I and Benjamin Franklin. Our story begins on the Planet Dzzt, where Cozmo's friend Nena is telling him all about birthday parties. Cozmo has never had a birthday because his planet takes a very long time to orbit its sun. Determined to help Cozmo find some birthday cheer, Nena, her uncle El Mundo the Great Wizard, and Cozmo's mother Azatara use math to discover that Cozmo will soon be 7 earth years old. Together they decide to follow Cozmo's love of math and create an Addition Celebration!