In the first chapter of The Hobbit, what exactly is Thorin's plan?

In the first chapter of The Hobbit, Thorin explains to Bilbo that his grandfather Thror had been King of the Dwarves of the Lonely Mountain. Under his rule the dwarves had mined deep into the mountain and discovered a vast source of wealth in gold and jewels. This wealth ultimately drew the attention of a powerful dragon, Smaug, who attacked the dwarven city, killing many of its inhabitants and scattering the survivors. As rightful heir to the kingdom, Thorin desires to set out for the mountain, and using a key to a secret entrance and a map provided by the wizard Gandalf, enter the city and reclaim the vast riches that are his birthright, despite the presence of the powerful and fierce dragon.