The Troll's Grindstone

To escape his enemies, Leifr agreed to impersonate the long-lost Fridmarr. But Fridmarr was one of the Alfar, as Leifr learned when he was taken into the legendary Alfar realms and given a magic jewel to aid the deception.

Fridmarr, he soon discovered, was hated by everyone. Forty years before, he had betrayed his people by helping the evil, powerful wizard Sorkvir despoil their land and destroy their weapons with a spell. Not content with that, Fridmarr had then betrayed Sorkvir, and Sorkvir had vowed to torture him to death if he ever appeared again in the Alfar realm.

To save himself, Leifr needed only get his hands on a certain magic sword and then find the troll's grindstone to sharpen it. But Sorkvir had hidden the grindstone. And the magic sword was hanging on the wall of Sorkvir's throne room!