The Fellowship of the Ring is the first volume of the epic novel The Lord of the Rings. It is divided into two books.
The first sets the stage for the adventure and follows Frodo Baggins as he flees from his home in the Shire to escape the minions of the Dark Lord Sauron. Sauron seeks the One Ring that will allow him to rule Middle-earth. This ring has been inherited by Frodo who finds himself unwittingly in the midst of a struggle for world domination.
Heeding the advice of the wizard Gandalf, Frodo leaves his home, taking the Ring with him. He hopes to reach Rivendell, where he will be safe from Sauron, and where those wiser than he can decide what to do about the Ring.
In his journey he is accompanied by three hobbit friends, Pippin, Merry, and Sam. From the start they are pursued by Black Riders, the Ringwraiths who serve Sauron. Narrowly escaping these and other dangers and meeting other interesting characters enroute (e.g ,Tom Bombadil) they eventually come to Bree, where they meet Strider, another friend of Gandalf who leads them the rest of the way to Rivendell, through further hardships.
Book Two chronicles Frodo's stay at Rivendell, where a plan is hatched to destroy the Ring in Mordor. Frodo sets forth with eight companions and a pony (see Fellowship of the Ring). Their attempt to cross the Misty Mountains is foiled by heavy snow, so they are forced to take a path under the mountains via Moria, an ancient Dwarf kingdom, now full of orcs and other evil creatures, where Gandalf falls into the abyss. The remaining eight members of the Fellowship then spend some time in the elf-kingdom of Lothlórien, where they receive gifts that in many cases prove useful later in the quest. They leave Lórien by river, but Frodo begins to realize the Ring is having a malevolent effect on some members of the party. This book ends when Frodo and Sam depart secretly for Mordor and the fellowship of the Ring dissolves.
See also: The Lord of the Rings: The Fellowship of the Ring for information about the movie.