The Hedge Knight is a short story by George R. R. Martin that first appeared in the Legends anthology, a collection of stories by various fantasy authors such as Stephen King. Robert Jordan. and Terry Pratchett. It was edited by Robert Silverberg. The story was later adapted into a graphic novel by Mike S. Miller. It is the first of the "Dunk and Egg " stories.
The story takes place in 209 AC. some 90 years before the events in A Song of Ice and Fire . It tells the tale of how Dunk took the mantle of a hedge knight and met his squire, a young boy named Egg. on his way to compete in a tournament at Ashford Meadow.
A hedge knight, Ser Arlan of Pennytree. has died during the night. His squire, a large young man named Dunk. buries him and pays his last respects. After considering several options, Dunk decides to continue his journey to Ashford and compete in the tourney as a knight. He adopts Ser Arlan's armor as his own, as well as his equipment, three horses, and remaining monies. At an inn on the road, he meets a boy with a shaved head named Egg who secretly follows him to Ashford. Impressed by the boy's spirit, Dunk takes him on as his own squire for the upcoming tourney.
At Ashford, Dunk sells one of his horses to commission armor, then attempts to enter the lists of the tourney. Without proof of his knighthood, he is nearly barred from competition until Prince Baelor Targaryen vouches for him. Dunk watches the first day of competition amongst the commoners, with Egg on his shoulders. After several spectacular tilts, the day ends when Prince Aerion Targaryen disgraces himself by killing Ser Humfrey Hardyng 's horse.
That night, Egg informs Dunk that a puppeteer girl he had met earlier is being beaten by Prince Aerion. Dunk leaps to her defense and attacks Aerion, striking him in the face. As the royal guard arrests Dunk, Egg reveals himself to be Aerion's brother, Prince Aegon. In jail, Dunk chooses to take a trial by combat rather than lose his hand. Prince Aerion demands the combat to be a Trial of Seven. as his brother, Prince Daeron. also accused Dunk of kidnapping Aegon from his charge. Dunk must find six champions to fight with him against seven accusing knights, or he will forfeit.
Steffon Fossoway is the first ally Dunk finds. He promises to bring Dunk more champions, as does Steffon's squire and cousin, Raymun Fossoway. Egg also promises to bring more champions for Dunk's cause. Raymun returns with Ser Humfrey Hardyng and Ser Humfrey Beesbury. good-brothers seeking revenge for the grievance Aerion committed against Hardyng. Aegon brings Ser Robyn Rhysling and Ser Lyonel Baratheon. the Laughing Storm, both eager for the glory of competing in the first Trial of Seven in a century. Steffon returns only to say he has decided to fight with the accusors for the reward of a lordship. Angered by his cousin's treachery, Raymun begs to be knighted and fight in Steffon's place. Dunk hesitates, but before he can give his answer, Dunk is called away by Lord Ashford, and Lyonel grants Raymun his knighthood.
Still needing a seventh champion, Dunk appeals unsuccessfully to the crowd. Finally, Prince Baelor announces that he will champion Dunk himself, though the accusers include three of his family members and three of his father's Kingsguard.
The fourteen champions line their mounts along opposite sides of the tourney grounds and charge. Dunk tilts against Aerion, but is quickly unhorsed. Though nearly defeated, Dunk manages to grapple Aerion and use his size advantage to pummel Aerion into submission. Aerion recants his accusation, ending the Trial. The fighting costs the lives of both Humphreys. Prince Baelor, who had not brought his own armor but instead wore armor made for his son, took a blow to the head from a mace. After the battle, Baelor approaches Dunk to congratulate him, and begins to act drunkenly. When his crushed helm is removed, it is shown that the weaker armor made for his son did not protect him from the blow which has crushed in his skull. Aerion's father, Maekar. meets with Dunk after the funeral, revealing that it was his mace that killed Baelor. He regrets Aerion's behavior and offers Dunk a position in his household to train Aegon. Dunk insists on being allowed to travel, and offers to take Aegon as his squire to learn to be a better knight than Aerion. Maekar agrees, making sure Aegon continues to use his alias of Egg to avoid scandal. Dunk and Egg set out to Dorne. in search of the puppeteer whom Dunk had saved.
Sources and Publications
The Hedge Knight was originally published in 1998 in the Legends anthology,  Legends II. is a completely different anthology, albeit by the same editor and having six writers in common with the original Legends. It includes the second Dunk and Egg tale, The Sworn Sword . The original Legends has been on occasion divided into two or three volumes, adding to the confusion. It is helpful to focus on the five writers that change between Legends and Legends II. Stephen King, Terry Pratchett, Terry Goodkind, Robert Jordan and Ursula K. LeGuin contribute to Legends but not to Legends II. while Robin Hobb, Neil Gaiman, Terry Brooks, Diana Gabaldon and Elizabeth Haydon have stories in Legends II but none in Legends. and later also in the GRRM-centric 2007 book Dreamsongs Volume II and as a stand-alone graphic novel.
Legends has often been republished and divided in two, three or four volumes.  The original Legends reaches over 700 pages and has ten other tales besides The Hedge Knight. The divided volumes will have less and it is easy to be confused about which ones include The Hedge Knight. 
It was once been divided into two volumes, both called Legends. The first one includes The Hedge Knight and four other tales, none of which involves the characters or the world of A Song of Ice and Fire. 
The Hedge Knight is also included in Legends Vol. 2.   which should not be confused with the completely distinct book Legends II. which first published the next "Dunk and Egg" tale, The Sworn Sword.
A compilation of the four initial "Dunk and Egg" stories, including The Hedge Knight. is expected to be published by Bantam.