A classic Moomin story reworked in full color, with a kid-proof but kid-friendly size, price, and format. It's getting hotter and hotter in Moominvalley, and all the creatures have taken note of the troubling weather. After a mysterious cloud appears in the sky one day, an exodus begins. The Hattifatteners, the Nibling, Mrs. Fillyjonk (and all her children), and even Mymble pack up to leave the valley. When they realize the mysterious cloud is a comet headed straight for Moominhouse, Moomin, Little My, and Snorkmaiden decide to depart their home too. Between a tidal wave and a comet-struck Moomin, the end does seem nigh, but the day may yet be saved!