|The Two Towers chapters|
As Gandalf and Théoden retreated from Isengard, the wizard carried Merry with him on Shadowfax, while Aragorn carried Pippin. Merry and Gandalf chatted. They rode late into the night and then stopped to camp. Pippin asked Merry whether Gandalf seemed different now that he had come back from the dead, and Merry replied that the wizard seemed both happier and more serious.
Merry was sleepy and tired of Pippin’s questioning, and he soon fell asleep. But Pippin, unable to sleep, was tormented by curiosity about the spherical stone that Wormtongue had thrown out of Orthanc. Pippin sneaked over to the sleeping Gandalf and snatched the stone. Pippin looked into it, unable to avert his gaze as the stone showed him Sauron, who questioned him. Gandalf awakened, angered at Pippin for taking the stone. After questioning him, Gandalf learned that the stone cast from Orthanc was one of the seven palantíri. This had allowed Saruman to communicate with Sauron. During Pippin's interaction with Sauron through the palantír, he managed not to reveal any important information about his company's quest. Sauron thought that Pippin was the hobbit with the One Ring imprisoned at Isengard, so he ordered Pippin to tell Saruman that the Ring would soon be retrieved, and Saruman could not have it. Expecting Sauron's messengers to come to Isengard soon, the host made plans to quickly leave. While discussing this, a winged Nazgûl flew overhead to Orthanc, the first time that any of the Nine had been allowed to go west of the Anduin after the loss of their horses and shapes at the Ford of Bruinen. This prompted Gandalf to immediate action: he commanded everyone to leave the area as rapidly as possible, and then he mounted Shadowfax with Pippin and started riding to Minas Tirith in Gondor.