Frodo, Sam, and Gollum finally arrive at the gates of Mordor. They behold the Teeth of Mordor, the tall towers built earlier by the Men of Gondor after the fall of Sauron, but then later reoccupied by the Dark Lord upon his return to power.
At the sight of the closely guarded gate, Sam wonders how they will enter. Gollum replies that they must not enter, prompting Sam to ask why they bothered traveling to Mordor in the first place if they cannot go inside. Gollum replies that he fulfilled his part of the agreement, guiding the hobbits to the gate. Sam is angry, again asking why they bothered going to Mordor at all. Frodo affirms that he must enter Mordor at all costs. At the hobbits’ insistence, Gollum admits that there is another way into the kingdom, a secret way that he discovered earlier. Sam distrusts Gollum, but the hobbits have little choice but to follow the creature’s lead. Frodo reminds Gollum that he has sworn by his “Precious” to guide them safely and not betray them.
Gollum directs Sam and Frodo toward a road that bends south around Mordor, telling them that the road extends for a hundred leagues, but warning that they should not go that way. Frodo asks if there is a third way. Gollum admits that there is a third path running around to the back of the kingdom, past a fortress built long ago by tall Men with shining eyes. Frodo realizes that Gollum refers to the former fortress of Isildur, the warrior who defeated Sauron and won the Ring from him. Part of the fortress is a tall tower called the Tower of the Moon. Sam asks whether the tower is occupied, and Gollum replies that it is guarded by Orcs and by even worse creatures called Silent Watchers. Sam remarks that this third path sounds just as risky as the first one, but Gollum says the Dark Lord is focusing his attention elsewhere. Gollum admits that the rear path past the Tower of the Moon is dangerous, but that it is worth trying. The hobbits are suspicious, but they accept Gollum’s advice.
Four Nazgûl appear in the sky overhead, and the hobbits know that Sauron is observing them. Frodo and Sam grab their knives, but they know that escape is impossible. Gollum senses that other Men are heading toward Mordor too—Men with long dark hair, gold rings, and red flags. He describes them as very fierce, saying that he has never seen anything like them. There are always Men entering Mordor now. Sam asks whether the men have “oliphaunts” with them, as he has heard the creatures described in old poetry. Gollum has never seen an oliphaunt. He urges the hobbits to sleep through the daylight hours, and proceed again at night.
The Teeth of Mordor and the fortress of Isildur are further reminders of the idea that evil can overtake and corrupt goodness. According to the moral system Tolkien puts forth, good and evil are not necessarily inherent qualities. The good can become rotten, as we have seen with Saruman and Boromir. This possibility of transformation from good to evil is also true of the buildings of Mordor. The Teeth of Mordor and the fortress of Isildur are reminders of the fragility of goodness, as the gentle and peace-loving Men of Gondor originally built them. Frodo is startled to realize that the ghastly fortress of Isildur, which Gollum reports to be full of murderous Orcs and the even more horrible “Silent Watchers,” was originally the property of the Lord of Gondor. Ironically, the building of the one who fought against evil is now possessed by that very evil. Good is not guaranteed in Tolkien’s universe, but must forever be actively guarded and defended.
The impossibility of entering the final destination directly, and the necessity of following a roundabout route to get inside, is a common element of ancient epics from which Tolkien has borrowed. For instance, in the Divine Comedy, Dante is, like Frodo, a traveler who is motivated by good but who is forced to go into the mouth of hell in order to reach heaven later. Dante cannot simply take the shortest path toward his goal of reaching heaven, but must travel through realms of evil he would otherwise never visit. Similarly, Frodo and Sam must travel to the heart of evil in Mordor in order to ensure the ultimate triumph of good. The hobbits, as usual, attain their goals not by direct confrontation; they plan to take the back road to a hidden entrance to Mordor rather than fight the guards at Mordor’s gates. Though the safety of this alternate route is doubtful at best, Frodo and Sam have little choice but to follow Gollum’s advice.