Showdown at the Tower of Joy

"Now it ends."

- Eddard Stark

The Showdown at the Tower of Joy was the penultimate engagement of Robert's Rebellion, a civil war that divided the Seven Kingdoms and led to the fall of the Targaryen dynasty and the rise of Baratheon rule.

Prelude
Following the Sack of King's Landing and the death of the Mad King, some loyalist forces still remained on the field, unaware of the fall of the capital and that Robert Baratheon had taken the Iron Throne. Despite their falling out over the murder of the royal family at the hands of House Lannister, Ned Stark went south to put an end to the Siege of Storm's End.

After Lord Mace Tyrell bent the knee and his siege of Storm's End had ended, a small group loyal to the Mad King still remained: the Kingsguard who had not been either at the Battle of the Trident or at the fall of the capital. When the rebellion had grown into a massive force that threatened the Iron Throne, Ser Gerold Hightower, Lord Commander of the Kingsguard, was dispatched by King Aerys to have Prince Rhaegar Targaryen return to the capital. Prince Rhaegar returned and would die in the Battle of the Trident, while Ser Gerold remained at the Red Mountains for unexplained reasons.

Events
At the Red Mountains of Dorne, Ned Stark and a small group of bannermen fought Ser Gerold along with his last remaining sworn brother: Ser Arthur Dayne. Hightower was killed early on in the fight, and the rest of the skirmish rapidly boiled down to a tense duel between Dayne and Ned Stark, in which Dayne eventually gained the upper hand and disarmed the Northerner, only for Dayne to be impaled from behind by Howland Reed and later executed by Stark. Ultimately, only Howland Reed and Ned Stark survived the fight.

Aftermath
Having dealt with the last Targaryen loyalists, Ned Stark returned home to Winterfell, along with the body of his sister, Lyanna Stark, who had recently perished, and his bastard son, Jon Snow, whom he had apparently fathered with a woman named Wylla. While his friendship with Robert was mended over their mutual love for Lyanna, who had been Robert's betrothed, both men would remain haunted by her death.

However, it is later revealed through one of Bran's visions that things didn't happen as Ned told everyone. After killing Dayne, he entered the Tower and found Lyanna, lying in a bed and bleeding massively from a cut in her abdomen. Ned calls the present maids for help but Lyanna stops and whispers to his ear. She makes him keep one last promise to her: keep her newborn son safe and protect him from the wrath of Robert Baratheon, who has developed a hatred for everyone carrying Targaryen blood, revealing that the child is Rhaegar's son. Lyanna then passes away and Ned returned to Winterfell with her body and her son, presenting him as his bastard, Jon Snow.

In the books
In the A Song of Ice and Fire novels, Ned Stark is accompanied by six men to the Tower of Joy, in the Red Mountains, to recover Lyanna Stark. The six men were:
 * Howland Reed
 * Willam Dustin, Husband of Lady Barbrey Dustin and the head of House Dustin
 * Ethan Glover, former squire to the late Brandon Stark
 * Martyn Cassel, father of Jory Cassel and brother of Rodrik Cassel
 * Theo Wull, of Clan Wull
 * Ser Mark Ryswell

When Ned Stark is injured fighting Jaime Lannister, he dreams about what took place at the Tower. He sees the three Kingsguard in their white cloaks and Lyanna "in a bed of blood." As he and his men come upon the Kingsguard, a dialogue ensues:

"::: “I looked for you on the Trident,” Ned said to them.
 * “We were not there,” Ser Gerold answered.
 * “Woe to the Usurper if we had been,” said Ser Oswell.
 * “When King's Landing fell, Ser Jaime slew your king with a golden sword, and I wondered where you were.”
 * “Far away,” Ser Gerold said, “or Aerys would yet sit the Iron Throne, and our false brother would burn in seven hells.”
 * “I came down on Storm's End to lift the siege,” Ned told them, "and the Lords Tyrell and Redwyne dipped their banners, and all their knights bent the knee to pledge us fealty. I was certain you would be among them.”
 * “Our knees do not bend easily,” said Ser Arthur Dayne.
 * “Ser Willem Darry is fled to Dragonstone, with your Queen and Prince Viserys. I thought you might have sailed with him.”
 * “Ser Willem is a good man and true,” said Ser Oswell.
 * “But not of the Kingsguard,” Ser Gerold pointed out. “The Kingsguard does not flee.”
 * “Then or now,” said Ser Arthur. He donned his helm.
 * “We swore a vow,” explained old Ser Gerold.
 * Ned's wraiths moved up beside him, with shadow swords in hand. They were seven against three.
 * “And now it begins,” said Ser Arthur Dayne, the Sword of the Morning. He unsheathed Dawn and held it with both hands. The blade was pale as milkglass, alive with light.
 * ''“No,” Ned said with sadness in his voice. “Now it ends.”"

As the two parties engage in battle, Ned hears his sister crying out his name, and the dream concludes with him making a promise before she dies. What exactly this promise entailed is unclear.