A patrol consisting of Will, Gared and Ser Waymar Royce set out into the Haunted Forest beyond the Wall. Will is later found hundreds of miles south of the Wall near Winterfell, apparently having gone renegade. He is apprehended and brought before Lord Eddard Stark for justice. Will claims that his companions have been brutally killed by the White Walkers and he fled in terror. Eddard does not believe the story and executes Will as a deserter, beheading him with his Valyrian greatsword, Ice.
After playing the role in the unaired original pilot, it appeared that Webb would be unavailable to reprise the character for re-shoots and would have to be recast. However, it was later confirmed that Webb would indeed be returning to the role.
In the books
In the A Song of Ice and Fire novels, Will is famed for his skills as a tracker and a hunter, a result of his previous career as a poacher. After being caught by Lord Jason Mallister's woodsmen, he chose to take the black over losing a hand. He has been on the Wall for four years when the events of the books begin.
In the TV series, some of Will and Gared's story roles have been switched around from the books.