Gilly
One of Craster's daughter-wives, a frightened, gentle girl desperate to escape her father's keep before her child is born.
A soul born at Beyond the Wall, sworn to The Free Folk.
The fuller tale
Season Two
One of Craster's daughter-wives at his keep beyond the Wall, pregnant and resigned to a life that has taught her not to expect kindness, from her father or from anyone else. She begs the Night's Watch rangers passing through for help if her baby is born a boy, because she knows exactly what Craster does with sons and none of the sworn brothers eating at his table want to admit they know it too. Sam is the only one who looks at her like a person rather than a problem to get past, and it's not nothing.
Season Three
Gives birth alone at Craster's Keep while the Watch mutinies against the Old Bear in the yard outside, and loses the argument over her own son's fate to Craster until the chaos of the mutiny makes the argument moot. Sam gets her and the baby out in the confusion, kills a White Walker with a dragonglass blade to do it, and drags all three of them south through a haunted forest with wildlings and worse behind them. She reaches the Wall on her own feet, half-frozen, still holding the baby she was told she'd never get to keep.
Season Four
Hidden at Mole's Town for her own safety while Sam mans the Wall against the wildling assault, and it is nearly the wrong call — Ygritte's raiders tear through the village and Gilly survives only by hiding herself and the baby in an empty oven while everyone around her is killed. She makes her way to Castle Black afterward in shock, and Sam, who spent the battle certain he'd sent her to die, finds her alive at the gate. It is the closest either of them comes to losing everything without a sword being involved.
Season Five
Settles into a version of safety at Castle Black that neither of them quite trusts yet, close enough to Sam that it becomes something more than gratitude. When Alliser Thorne's mutineers and a band of Thenns storm the keep, she fights alongside Sam rather than simply hiding behind him, and it's the first time either of them treats her as anything other than someone who needs protecting. When Sam decides to go to Oldtown and become a maester, she and the baby go with him, onto a ship bound for a city that has never had any use for wildlings.
Season Six
Brought to Horn Hill and introduced to Sam's family as exactly what she is, and Randyll Tarly makes his contempt for that plain over dinner, in front of his son and grandchild both. Gilly holds her ground at the table in a way Sam himself can't quite manage, and it's her presence as much as his father's cruelty that finally decides him — he steals the family sword and they leave together in the night. In Oldtown she and the baby wait through Sam's long apprenticeship in a small rented room, a wildling girl learning to read in a city built on believing people like her don't.
Season Seven
Still teaching herself to read in Oldtown, and it's Gilly, not Sam, who stumbles on the detail that matters most — an old High Septon's account, read aloud half as a curiosity, of a prince's marriage annulled and remarried in secret. Sam barely registers it at the time, too tired of copying scrolls to notice he's holding the answer to a question half of Westeros is fighting over. By the end of the season she's had enough of the Citadel's slow uselessness in a fast war, and leaves for Winterfell with Sam and the baby, pregnant again herself.
Season Eight
Arrives at Winterfell a stranger among lords, pregnant, with a small son who has never seen snow like this before, and settles in as if daring anyone to comment on any of it. During the Battle of Winterfell she shelters in the crypts with the rest of the women, children, and old men, which turns out to be far from the safest place in the castle once the dead start climbing out of the very stone around them. She survives it, and by the season's end she is still at Sam's side, waiting on a second child and whatever quieter life a maester's family gets to have now.
How it ends for them
The chronicle records no death for this soul — they are living when the tale leaves them, or their ending is a page the maesters have yet to turn.
Their chapters, book by book
A Storm of Swords 2 chapters that name them
A Feast for Crows 1 chapter that name them
Where the page and the screen part
The great divergence is the baby swap. In the books, Jon Snow — fearing Melisandre will burn any child of king’s blood — secretly exchanges Gilly’s son for Mance Rayder’s newborn and sends Gilly south nursing the wrong child, an act of cold arithmetic that leaves her grieving down the whole length of the voyage to Oldtown; her ship-board sorrow, and Sam’s guilt, color everything the books do with them. The show cuts the swap entirely, and with it that grief: screen-Gilly keeps her own boy, and her journey with Sam runs through invented stations — Mole’s Town under wildling attack, the frosty dinner table at Horn Hill, the Citadel’s scullery — toward a settled domesticity the books have not yet granted. Her diary discovery about Rhaegar’s marriage is likewise pure show; on the page the secret sleeps elsewhere.
Their journey
Where the two tellings send them to the same place the road runs whole; where they part, the screen keeps the left and the books the right.