Ch. 10: What do they learn from Strider in the parlour?

Strider tells the hobbits that the Black Riders have been looking for Frodo. Butterbur, a friend of Gandalf, also appears, producing a letter he was supposed to have mailed to Frodo three months earlier. The letter from Gandalf is a warning to Frodo instructing him to never use the ring. Gandalf also states that Strider (Aragorn) is a friend.