The Lonely Mountains

Official website description
Moominvalley is surrounded by the Lonely Mountains, a high mountain range in the east, feared by many as an unknown and slightly scary space inhabited by the Groke. In the book Comet in Moominland, Moomintroll learns that a comet will be passing by Moominvalley and travels by advice of the Muskrat with his friend Sniff to the Observatory on the Lonely Mountains to consult the Professors.

The Hobgoblin, a powerful magician appearing in the book Finn Family Moomintroll, travels the universe with his flying panther, looking for the King’s Ruby. His top hat is found in the Lonely Mountains by Moomintroll, Snufkin and Sniff, who bring it back to the Moominhouse with unintended consequences.