Once Gandalf deafeted the Balrog he then died. But the Valar gave him a new body and he was Gandalf the White. He is Saruman some could say. Gandalf uses a Rohirrim horse named Shadowfax who is also the lord of all the horses he is also the fastest horse known to Middle-Earth. The first apperrance of Gandalf the White is in The Lord of the Rings The Two Towers in Fangorn Forest where Aragorn, Legolas, and Gimli mistake him for Saruman and attack him but Gandalf defleckes all their attacks. Then he tells them his tale of the perilous fight with the fire demon. He then tells Aragorn and his two companions that they need to go to Edoras to save King Theoden (he is the king of Rohan) from Sarumans evil grasp. When they get to the Golden Hall of the king they find the sly Grima Wormtongue speaking lies to Theoden. Gandalf takes king Theoden out of Sarumans hands and Theoden throws Grima Wormtongue out of Rohan.
After that, King Theoden decides to have everyone go to the fortress called Helms Deep where he thinks his people will be safe. Gandalf tells Aragorn to stay with the king and to help him while he goes to get the Riders of Rohan. Meanwhile Grima Wormtongue leaves the King. King Theoden decides to go and fight Sarumans forces but they end up going to Helms Deep. Gandalf leaves the riders and goes to Isengard where he talks to an Ent named Treebeard and gets some Ents that are more like trees than Ents to help the king. Next Gandalf gets some of the kings men and takes them to Helms Deep to defeat the 10,000 Uruk-hai and wild men of Saruman.
After they defeat Sarumons forces they go to Isengard where Merry and Pippin greet them and tell them where they can find Treebeard, they also tell them that Saruman is stuck up in his tower and so is Wormtongue. Gandalf and the others go up to the front door, Saruman comes out to them but he stays in his balcony and tries to enchant them with his voice the king doesn't fall for it. Saruman gets angry when Gandalf tells him to surrender and he starts walking away but then Saruman gets pulled back by Gandalf's power, Gandalf then brakes his staff and takes the top half and banishes Saruman from the head council. After that Wormtongue throws down the Palantir but thankfully he missed them and Gandalf takes the Palantir (the Palantir is an ancient seeing stone there are only three accounted for but they all have different names but Gondor has one Gandalf has one and Barad-dur has one.) then they take the two hobbits and leave for Helms Deep.
On the way Pippin takes the Palantir and looks into it. When he looked into it he saw Sauron, but Sauron thought he was at Orthanc and that Saruman was having him look into the Palantir as a punishment so he didn't question him. Pipppin makes a shriek wakes the entire camp, gives the Palantir back to Gandalf, Gandalf gives it to Aragorn and takes Pippin and leaves for Minas Tirith on Shadowfax.
Once Gandalf get's to Minas Tirith where there is a battle between the men of Gondor and Mordor. Gandalf safes Faramir who was badly poisened (Faramir is Boromirs brother) from be killed by his father(his father looked into another seeing stone of Gondor). Then Aragorn and the others get there and they win the battle. They know that Frodo and Sam are close and they make a decision that they have to attract all the attention of the eye, so they take a huge army to the gate of Mordor where they are met by the Lieutenant of Mordor who told them to surrender to him but they didn't and then they started the battle of Mordor.After a while of fighting the eagles come and save them. Gandalf sends an three eagles to Mount Doom to save Frodo and Sam meanwhile Frodo finally destroys the ring but I'm not gonna tell you how but the eagle get's there just in time because Mordor blows up and they would have blown up too but the ring is finally destoyed!
Did you think that that was the end of this story, next they go to Isengard and see that Sarumon looks like just an old beggar then Gandalf telles the hobbits that they are going to have a very hard time and has them go back to the Shire then Gandalf comes later and tells Frodo that he has to go with him the undying lands and so does Bilbo and Galadril Sam has to go to but he goes later(they have to go because they had a ring and they would get very sick) Gandalf tells them that he has to go too because he has the Elvish ring Anor. But Aragorn became the king of Gondor and peace was restored in Middle-Earth. That the end of the story of the Lord of the Rings.