The second book in the Lord of the Rings trilogy, J. R. R. Tolkien's The Two Towers continues the story of the quest begun by Frodo and his company in the Fellowship of the Ring. Frodo and his servant Sam Gamgee have been separated from the rest of the company, and the book follows the adventures of both parts of the company.

While Frodo and Sam continue with the Ring on their journey to the Cracks of Doom, the evil power of Sauron that had begun to rise in the first book now has his forces everywhere they and the others of their broken company go. He has Riders and spies out searching for the Ring and those who would defend it, but for the men fighting to keep the Ring from enemy hands, that is still not the primary threat for the moment.

The chief wizard, Saruman the White, who has shown his true colors as a traitor, takes further steps to gain the precious Ring all for himself, and the company must overcome his fortress, the tower of Orthanc, at Isildur to protect the Ring-bearer Frodo as he continues on. His own journey takes him and Sam into the dark land of Mordor where they meet an old acquaintance who plays an important role in the tale of the Ring.

The final chapter of this tale is recorded in the Return of the King, the third book in Tolkien's trilogy.