The Two Towers · Chapter 13
Frodo Captures Gollum
Stranded on the Emyn Muil, Frodo and Sam endure Gollum's pursuit. Frodo's resolve hardens with grim determination and pity; he spares Gollum's life and subdues the creature, who swears allegiance by the Ring to guide them.
Outcome
Gollum becomes their reluctant guide; Frodo's mercy plants seeds for later events; they venture toward the Dead Marshes.