Return the Dragon Stone to Farengar Secret-Fire. He will only accept the Dragonstone after the quest "Dragon Rising" has begun. If the stone has been obtained before Bleak Falls Barrow has started, then it can be turned over to him immediately.
Presenting the Dragonstone to Farengar automatically starts the "Dragon Rising" mission. Upon completion of "Dragon Rising," the game world irrevocably changes and the Dragonborn is thereafter subject to random dragon attacks, which not only makes travelling around Skyrim hazardous (especially for low-level players), it occasionally results in the death of non-essential NPCs who may still have quests to be completed.
|HET NOK UN|
ERei SULeyK SE
|HERE LIE OUR|
UNTIL POWER OF
- The Dragonstone was seemingly originally intended to be a book, since all comments and references in the scripts and creation kit refer to it as 'the book' that the Dragonborn must retrieve.