Thorin, who had been captured earlier, is no longer alone, for the rest of the company also became captured by the wood-elves. Except Bilbo of course who slips on his ring and slips into the wood-elves’ caverns undetected.
Bilbo spends probably two weeks in the caverns, trying to figure out how to rescue his friends who have all been locked up in cells, but given food. We get a nice balancing act here of Bilbo’s two natures; his cunning and cleverness is slightly gives way to his Baggins side who wants to go back home. But he doesn’t abandon his friends or give up all hope. Eventually, he discovers Thorin in a cell deeper in the caverns and it was a good thing too, because Tolkien tells us that Thorin had almost given up until Bilbo comes to him. It’s fascinating how Thorin has come to view Bilbo now, although their new friendship will be severely tested in later chapters.
Bilbo’s plan to rescue the elves by shoving them in wine barrels and sending them down a trap door into a river is pretty comical. Of course Tolkien plays that up for all its worth with descriptions of angry dwarves, lids not closing, and extremely heavy barrels picked up by the raft men. Of note however, in the history of fairy stories and folklore, there is no other similar event that Tolkien has pulled from. Tolkien who is the master of incorporating classical fairy tale elements into his own story, comes up with his own idea here, and it’s really quite exciting how Bilbo sneaks around in this chapter to pull it off. The dwarves are now utterly and wholly dependent upon him, and pretty much for the rest of the book Bilbo becomes the defacto leader and problem solver.
One small detail that I do feel is quite odd, is that the Elvenking is never given a name in The Hobbit. In LOTR we later learn his names, and we also learn that he is the father of Legolas. You have to wonder, if Tolkien finished his huge rewrite of The Hobbit the he abandoned, would Legolas have made an appearance?