Margaery Tyrell
Mace's daughter, clever and gracious and quietly ambitious, who understands the winning of a crowd — and a king — better than anyone at court.
A soul of House Tyrell, born at Highgarden.
The fuller tale
Season Two
Arrives at Renly Baratheon's war camp already married to him, poised and pragmatic about a marriage that is politics dressed as romance, and unbothered by what the marriage actually is behind closed doors. When Renly is murdered by the shadow Melisandre births, Margaery loses a husband and, with her family, promptly sets about arranging a better one — the Iron Throne looks a great deal more reachable through Joffrey Baratheon than it ever did through Renly, and she and her grandmother move toward it within days of the funeral.
Season Three
Engaged to Joffrey now, and visibly better at being watched by a crowd than either of the Lannisters she's marrying into — visits orphanages and war hospitals, praises the smallfolk to their faces, and lets Joffrey believe every bit of goodwill it earns her is really about him. Wins over young Tommen with nothing more than a kitten and some patient attention, laying groundwork nobody but her grandmother seems to notice she's laying. Cersei watches her with open suspicion and gets nothing back but courtesy, which needles Cersei considerably more than an argument would.
Season Four
Marries Joffrey at last in a wedding built to be remembered, and it is — he collapses choking at his own feast and dies in front of the whole court, leaving Margaery a widow before the wine's finished pouring. Grief lasts about as long as the funeral; within days the Tyrells and Cersei alike are discussing a match with Tommen instead, and Margaery is visiting the new king in the training yard before the old one is cold in his tomb.
Season Five
Marries Tommen and sets about being the wife to him she could never quite be to his brother — warmth this time, or close enough to it that Tommen can't tell the difference, which is rather the point. Wars quietly with Cersei for the boy king's attention and wins, easily, simply by being kinder to him than his mother knows how to be. It costs her: the High Sparrow's Faith Militant, revived with Cersei's blessing, arrests Loras on old charges and then arrests Margaery too, for swearing under oath that she knew nothing about them.
Season Six
Held by the Faith through the winter, alternately defiant and, eventually, convincingly pious — enough that by the time she's released she has both the High Sparrow's trust and Tommen's ear, and appears, to everyone including Tommen, to have found real religion. What she's actually doing is running out the clock, trying to walk her family and her husband's throne through the Sparrow's grip without a war, and she comes closer to managing it than anyone expects — right up until the Sept of Baelor and everyone inside it goes up in wildfire beneath her.
How it ends for them
On the screen. Died when the sept burned (S6·E10)
The thrice-wed queen read the room the way she always did — she knew Cersei's absence meant death, and tried to empty the sept. The High Sparrow's certainty barred the doors, and the wildfire spared no one, not even the cleverest.
In the show she dies of being the only person in the building who understood it. At Loras's trial in the Great Sept, Margaery reads the room the way she reads every room: Cersei is absent, Cersei who never misses a triumph, and therefore the triumph is the building. Her warning is immediate and correct — she tries to force an evacuation, breaking her penitent's mask for the first and last time — and the High Sparrow's serene refusal bars the doors until the wildfire beneath the sept ends the argument. The explosion kills her, her brother, her father, and the Faith entire; the cleverest player in King's Landing loses to the one player willing to burn the game. In the published books Margaery is alive, released to await a trial that has not yet come, her endgame unwritten.
Their chapters, book by book
A Clash of Kings 1 chapter that name them
A Feast for Crows 4 chapters that name them
Where the page and the screen part
The show ages her up and moves her to center stage; the books keep her at a teenager's remove, seen only through others' eyes — mostly Cersei's, a narrator whose paranoia the reader must constantly discount, which is the books' sly trick: Margaery's true interior is one of the saga's deliberately withheld cards. Book divergences run through her whole file: her marriage to Renly is unconsummated by her own testimony, the Joffrey match ends at the purple wedding before any wedding night, and her arrest is engineered through a suborned knight confessing to her adultery — with her trial by the Faith still pending as the published books close, her cousins imprisoned beside her and a Kingsguard champion in the offing. The show's crossbow diplomacy, Sparrow alliance, and sept endgame are all its own construction.
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.