Momo and Komomo can deliver mail from anyone, to anyone. To anywhere in the world, the galaxy, or the universe. Under the sea, high up in the clouds, and around the corner. To the past, the present, or the future. They both work tirelessly to insure that the important letters of people are delivered, while Komomo also works hard to keep the ever distracted Momo on task.

(Source: Anime News Network)