The Mumpf has written twenty-seven letters to his best friend, the snowy owl! She has traveled to the North, where it is winter even in summer. But one day, the Mumpf discovers that the self-made mailbox in the forest is never emptied. The owl hasn’t received a single letter from him – doesn’t she have to think that he has forgotten her? He decides to bring her the letters himself. But a journey means preparing, packing, and above all, saying goodbye: to the summery Mumpf forest, to the old mole who would have liked to come along, and to the friendly ermines. Not easy, the Mumpf suddenly finds. And above all, dangerous, claims the mole. Because what if the Mumpf encounters a Mumpf-eater on the way?.