The Game of Thrones writers will be diverging from George R. R. Martin's A Song of Ice and Fire book series for parts of season 4.

A new photo has surfaced featuring the location used for Craster's Keep. The Production Diary for Game of Thrones posted the photo, saying that they were filming new material there for season 4. Craster's Keep is not featured in the latter half of book 3, which Game of Thrones is covering for season 4.

Craster's Keep was the location of the mutiny in season 3 that resulted in the death of Commander Jeor Mormont (James Cosmo). This is the last event at Craster's Keep in book 3, which means that the Game of Thrones writers must be inventing more story lines to be shot there. See the photo here.

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As for what will be shot at Craster's Keep, Game of Thrones fan-site WinterIsComing.net via ComicBookMovie.com confirmed that the footage will "involve both Jon's (Kit Harington) and Bran's (Isaac Hempstead-Wright) storylines."

As far as other story lines that will be covered in season 4, the show is expected to be covering everything from the middle to the end of book 3, A Storm of Swords. The events featured at the end of the book are huge turning points in the series, featuring deaths of major characters, significant wars and potential marriages.

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Game of Thrones season 4 premieres on HBO in spring 2014, though the network has not yet scheduled a premiere date.