Strider is the tenth chapter of the first book in The Fellowship of the Ring.
Strider follows Frodo to his room, which makes Frodo very uneasy. Strider tells Frodo that he knows his real identity and warns him of the Black Riders. He also warns them of a few Hobbits of Bree who are up to no good. He asks to join them. Despite his offers of assistance, however, Strider is unable to gain Frodo's trust.
At that moment, Mr. Butterbur comes in. He tells Frodo that Gandalf has left a letter for Frodo. After giving Frodo the letter and saying he will be on the lookout for Black Riders, Mr. Butterbur leaves.
Frodo reads the letter that warns him against traveling at night and against using the ring. Gandalf has also written about Strider, saying that he is a worthy friend. The letter also tells Frodo to make for Rivendell with haste.
Strider tells the Hobbits that his real name is Aragorn and that he will protect them. They all wonder what has happened to Gandalf to make him send someone else to give the message.
Suddenly Merry comes in and tells them that he was out for a walk and saw a Black Rider. When he followed the shadow it disappeared. Merry was then overtaken by the Rider's breath and fainted. But before any harm could come to them, the landlord's helper Nob came to his aid.
Strider warns the Hobbits that they are in danger. He says a Bree man named Bill Ferny must have told the Black Riders the Hobbits were there. Strider tells the Hobbits not to sleep in their own rooms. They carry their belongings to another room and finally go to sleep.