Thorin's grandfather, Thror, brought the dwarves and their mining tools to the Lonely Mountain. All day and all night, they worked hard mining, until they discovered a whole cave of sparkling jewels and gold. They became wealthy and Thror was crowned the King of the Mountain, ruling over the people of the town of Dale in the valley. Before long, the luxurious amount of treasure brought unwanted attention. Smaug, a dragon, came to Dale and breathed fire on the people and houses. Many were killed or injured, but through a secret way, Thror and Thrain escaped. Yet, they only had the chance to hand Gandalf the Map and Key to give to Thror. Ever since, the dragon has been protecting the gold. Now, with other dwarves, Gandalf, and possibly Bilbo Baggins' help, Thorin will be able to win his family's gold and jewels back from Smaug.