2. The Second Prologue Focuses On Bilbo's Party Planning
Immediately after the story of Smaug's destruction of Eribor and the dwarves' forced exile, the story jumps back to Bag-End where Ian Holm's old Bilbo sits writing the account of Eribor's attack, only to be interrupted by the presence of Frodo, who brings a large pile of letters from the post-box and confirms that they are responses to Bilbo's party invitations. We quickly learn that the leaving party from the very beginning of the Lord of the Rings is set to happen later the same day, and Bilbo and Frodo briefly discuss whether Gandalf will turn up, before Frodo goes off to his Fellowship Of The Rings hiding place to surprise the wizard. At that point, Bilbo settles down to tell the story of how he first met Gandalf, and the party of Dwarves, and the film gets into its full swing. The decision to include Frodo feels somewhat superfluous, especially considering Elijah Wood is quite remarkably different in appearance from when he filmed the LOTR trilogy. He looks markedly taller and more lean, and anyone who has watched the LOTR trilogy even semi-frequently will feel the jarring effect - but you can see why Jackson chose to include it, as a sort of fan service. And it does offer a small narrative frame for Bilbo to narrate his own story.