It is Bilbo Baggins (Martin Freeman) who discovers a weakness in Smaug the Dragon's armor in The Hobbit: The Desolation of Smaug. Arriving in Lake-town, also known as Esgaroth, the Hobbit will inadvertently reveal his secret to Bard the Bowman, ultimately leading to the defeat of this magnificent golden beast. We have your first look at Bilbo's arrival in Lake-town, wrapped in a blanket, in full protection of the dwarves.
"...the dwarves' good feeling towards the little hobbit grew stronger every day. There were no more groans or grumbles. They drank his health, and they patted him on the back, and they made a great fuss of him; which was just as well, for he was not feeling particularly cheerful. He had not forgotten the look of the Mountain, nor the thought of the dragon, and he had besides a shocking cold. For three days he sneezed and coughed, and he could not go out, and even after that his speeches at banquets were limited to "Thag you very buch."