Bibo's first assignment as a burglar is to investigate the source of the light that his party sees in chapter 2. Bilbo, being an amateur burglar with no proper experience, finds that his first caper goes off with quite a few hiccups.

The party has just lost their provisions and are sitting around feeling dejected. That is when they spy a light through the trees. The dwarves agree that Bilbo, being a burglar, is the best man to investigate. They assume that he will be stealthy enough to find out if "all is perfectly safe and canny."

Bilbo is not too eager to investigate but he finds that he has little choice in the matter. Even though he is not a proper burglar, Hobbits are stealthy creatures and Bilbo approaches the source of the light unnoticed. To his horror, Bilbo discovers three large and grumpy trolls roasting and eating mutton over the fire.

Despite his hesitations, Bilbo decides to fulfill his role as a burglar and pick the trolls' pockets. Unfortunately for Bilbo, he is caught in the act and captured by the trolls. However, the trolls start fighting among themselves and Bilbo escapes. At this moment, the dwarves start showing up one by one and they are captured by the trolls.

As the trolls sit around trying to decide how and when to cook the dwarves, Gandalf sneaks up. Using his power to imitate the troll's voices, he gets them fighting with each other once again. Eventually, the sun comes up and turns the trolls to stone, allowing the dwarves to get away.