It's Kai's 8th birthday, and he's having a party! But his party is still hours away, and he and his sister, Faith, are bored. They ask Nanny if they can take her Time Machine to go visit Vera, but Nanny has a better idea. She lets them take her spaceship to a new planet, reminding them to be back at 5:00 sharp.
 

They end up finding a Unicorn Planet filled with rainbows, sweet-tasting air, and, of course, unicorns! After helping a baby unicorn named Clover get unstuck from a log, they returned home only to discover that she snuck onto their ship! It's already 4:00, and now they have to bring the baby back to its mother and return all before 5! Unfortunately, they can't remember where the planet is! Will they make it back in time for the party? And more importantly, will Clover get back to her mother?