Here's your burglar. Thorin and company, meet Bilbo.
They... they made a mess of my house!
Come, Bilbo! We have a dwarven kingdom to reclaim from a dragon!
While passing through the mountains, the party was captured and taken underground by goblins. Bilbo was separated from the rest as they made an escape, and found a curious gold ring on the ground.
I wonder what this could be...
While trying to find his way out, Bilbo met a sad creature named Gollum, who agreed to show him the way out if he won a riddle contest.
What have I got in my pocket?
We do not know! It is not fair, my precious, to ask what it has in its nassty pocketses!
Bilbo escaped, finding out that the ring was a magic one that could turn him invisible in the process. He found the rest of the group again, and Gandalf took them to the house of Beorn, a man who can turn into a bear.
You may stay for a time to rest and get supplies.
Thank you very much, sir. Do you have any advice how to get through Mirkwood?
Gandalf left to attend to his own business, and the rest departed into the ominous Mirkwood forest. After running out of supplies, they ventured off the path and most were caught by giant spiders. Bilbo, however, was not.
I can use this ring to turn invisible and save the dwarves from those spiders!
Unfortunately, immediately upon their escape from the spiders, the dwarves (except Bilbo, who went invisible once again) were taken prisoner by the elves that also lived in the forest. Bilbo was able to once again get his friends out of trouble, by sneaking them onto barrels that were floated out of the forest.
A little uncomfortable, but very good plan Mr. Baggins!