The story revolves around Princess Comet, a twelve year old girl who is also the princess of the Harmonica Star country of the Triangle Nebula. She was meant to meet the prince of the Tambourine Star country, but the prince ran away to Earth instead. As it turned out, Comet is sent to Earth to find him, though she has no idea what he looks like.
Once she travels to Earth, Comet falls in love with the people she meets there as well as the planet itself, quickly becoming attached to life on Earth. Meanwhile, Princess Meteor learns of Comet's plans to find the prince and to marry him and she arrive on Earth in search of the prince as well, planning to marry him before Comet gets the chance.