After witnessing her father's murder, Sansa plots her revenge. Hearing of the discovery of caches of wildfire under the Great Sept of Baelor, Sansa begins to visit the Sept with greater frequency in order to obtain some of the highly flammable substance. She gets lucky, as she is able to steal a wildfire jar from an unsuspecting acolyte of the Alchemist's Guild.
Aware that Joffrey is usually protected by more than one member of the Kingsguard, she decided to make her move on one of three targets: Cersei, Tommen or Myrcella. To this end, Sansa starts calling on the Queen more often, and makes several overtures to the younger Royal siblings. While her meetings with the Queen are not only severely uncomfortable and often humiliating, she comes to like the "Baratheon" children as they have nothing of their mother or older brother's viciousness. Thus, even though she greatly desires revenge for the death of her father, Sansa realizes that she is incapable of hurting the younger children.
As Sansa plots, however, the war worsens, and Robb begins to make great headway as a military leader, winning more and more battles, finally culminating in the capture of the Kingslayer. As a result, Sansa is beaten in front of the court on Joffrey's orders and then Cersei demands that she be confined to her room. Angry and humiliated, Sansa decides, rather brashly, to put her plan in motion.
While in her room, Sansa calls for a maester (Frenken) and convinces him that rather than the much milder dreamwine, she requires large doses of milk of the poppy, as she is unable to sleep and suffers through great pain. One night, Sansa is able to drug her guards and servants with wine and food laced with milk of the poppy. Ser Ilyn Payne, who had been sent to guard Sansa by Cersei is also drugged, and Sansa is able to reclaim the Stark's ancestral sword, Ice. She proceeds to behead the drugged Ser Ilyn in a fit of rage.
Before leaving her room, Sansa considers trying to take the Baratheon children with her but ultimately decides that she bears no responsibility for them, and that simply having made sure that they were in the Godswood is enough. Satisfied, Sansa lights a fire in her room.
She is able to make it to the stables by the time she hears an explosion in the upper levels of the castle, and sees that a large swathe of it is engulfed in green flames. In the chaos of the fire, Sansa is able to make her way out of the Castle grounds, and into the city of King's Landing itself. Sansa finds herself at the docks and, utilizing the coins she had stolen from her guards pockets, Sansa is able to pay for a boat to take her across the Narrow Sea to Braavos. As the boat makes its way across the waters, Sansa looks back at the Red Keep, now almost entirely bathed in green fire and smiles.
After Sansa weeks on the treacherous sea, Sansa discovers that the sailors do not intend to take her to Braavos, but instead plan on selling her to the highest bidder at Yunkai. There, they intend to make her a bed slave. Sansa discovers that the slavers have been complaining to the captain that they should be able to have some "fun" with her, but the captain is adamant that Sansa remain untouched as the Yunkai would pay her weight in gold, as a virgin of Sansa's beauty and colouring in Essos is a rare find. The captain is forced to kill a shipmate who attempts to assault Sansa, and though it is obvious that the other sailors aren't happy, the Captain is able to restore order to the ship.
Tensions run high on the ship, and to appease the sailors, the captain authorizes a raid of the Summer Isles The raid is successful, and after securing all the women, they returned to the seas. Sansa is greatly disturbed by the fate of the Summer Islander women, and becomes extremely protective of a young orphaned summer islander child, Sola, who is constantly crying. Sansa attempts to shield Sola from the horrors of their life as captives.
The raiders become rowdy again when discontent grows because the Captain has selected four of the women for himself and insisted that the other shipmates must share the remainder. The sailors mutiny, and in the chaos of the fighting, Sansa manages to free herself and most of her companions, who are able to successfully take over the ship. The sailors are brutally murdered and only one, heavily bound is kept alive to steer the ship. As they are close to Naath, Sansa and the crew dock there. Sansa is taken with the peacefulness and beauty of Naath, but when the lone remaining sailor dies, and Sola begins to show signs of having acquired the Butterfly fever, Sansa is adamant that the crew depart the island.
Setting out to return to the Summer Isles, the seas, already treacherous, become even more dangerous when a storm hits, and the ship is forced to make an emergency landing on what they believe to be Sothoryos. With a damaged ship, the crew is unable to depart, and they set about scavenging the land for supplies. Sansa is the first to realize that they aren't in Sothoryos, but instead the ruined city of Valyria. Most of the crew becomes agitated when she finds out, and Sansa, largely ignorant of history beyond the fairytales, is told of the story of Valyria. Sansa is ashamed that she could not know such an important part of World History.
Sansa becomes increasingly concerned for Sola, as the child has been very ill since their stop in Naath. While delirious, Sola tells Sansa of her dreams: a butterfly led her to a castle made up of snarling dragons, and the wolf's howl was heard throughout the world. Sansa is confused by the dream and quickly puts it aside. She devotes her energy to nursing her back to health while trying to assist the crew in fixing the ship. Another passing storm however causes the ship to be damaged even further.
The crew decides that they must go further inland in or face starvation, as they have yet to come across any food. As they wander, however, the group begins to experience strange phenomena: one of the group goes mad and slits her own throat and her lover's; two others wander off, convinced they heard voices. Slowly, but surely, the group traverses the island, and finds itself, with much reduced numbers, at the ruins of a once-great city. On the first night of exploring the ruins, Sansa finds a black dragonglass candle and immediately gets a vision of the Doom of Valyria which then morphs into a vision of the night she burnt down King's Landing. As she sleeps, Sansa begins to dreamwalk frequently and is able to form a basic understanding of the state of her family in Westeros.
Sansa begins attempting to conscientiously warg. Sansa and Sola discover great riches within the city but Sansa questions their utility if she has no means of leaving the island. Sola reminds Sansa of her fever dream, and Sansa begins to suspect that her warging ability is the key. Sansa continues to hone her warging abilities and soon is able to project herself into animals. This discovery allows for Sansa to warg into a bird, and she is able to follow a flock to a forest, a ways off of the ruins, in which animals are alive. Sansa and Sola are able to make it, but their final companion, Xanda reveals that she has contracted greyscale and is unwilling to risk infecting them and the animals. Before Sola and Sansa can protest, Xanda committs suicide. The girls are shaken by the turn of events, but are grateful to finally be free of the rot of Valyria. Sola proves to be quite adept at killing and preparing a huge hog, and for the first time in weeks, the girls have a proper meal. As they prepare to sleep, Sansa and Sola are mesmerized by the forest that they come to realize is actually magical. The forest seems to guide them on and soon they arrive at a shore, where they are surprised to find a ship, The Firebird, waiting. Aboard the ship is a contingent of followers of the Red God.
Sansa learns that the followers of R'hllor received visions of Sansa and Sola's plight, and that Sansa actually appeared to them. The head priest, Aramis of Volantis, has splintered from the rest of the red priests and has come to believe that Sansa will play an important role in the upcoming battle for light. Sansa thanks the red priests for their assistance, and asks them to set course for the summer isles to drop Sola back off. Sola, however, is adamant that she continue to accompany Sansa. Both are overjoyed. Sansa then asks the red priests to plot a course for the North.
While on the Firebird, Sansa attempts to understand the religion and amazed by their magic, Sansa asks to be taught as well. Aramis is eager to encourage Sansa's interest in the religion and agrees wholeheartedly to teach Sansa what he knows. Sansa discovers an affinity for fire, but remains largely sceptical of the religion as a whole. Aramis is bemused at Sansa's hesitance to accept the religion, and points out that Sansa has, in effect, already served as one of R'hllor's best priestesses. Sansa does not understand Aramis' comments but does not ask for clarification.
In the presence of the dragonglass candle, magic is empowered, and the red priests visions become much clearer. Sansa, as a novice, can only see Robb at the gates of Casterly Rock. The more experienced priests warn her to look beyond the obvious, and are able to show that Tywin Lannister, is conspiring with Robb's allies, the Boltons and Freys. Sansa attempts to warn Robb of the danger, but the red priests inform her that that is beyond her, and their abilities. The red priests indicate that, with a sacrifice, Tywin could be killed. They suggest that Sola be sacrificed, as her innocence will be pleasing to the Red God. Sansa is horrified at the suggestion, and severely reprimands the priests. Instead, Sansa orders the Red Priests to deliver her to a free city in which she can send a raven to warn Robb, and assemble a host to defeat their enemies. Aramis directs the ship to Tyrosh.
In Tyrosh, Sansa meets with representatives of the Wolf Pack, the Company of the Rose, and the Golden Company and attempts to contract their services. The Company of the Rose mocks her as a "Stark Kneeler" and refuse to do business with her. The Wolf Pack accepts her offer on the condition that a lordship be given to its commander, Kato, the mixed-race son of a Mormont and a minor Dothraki Horselord. Sansa has no difficulty in promising such a thing, but shows some negotiating skills when she is able to convince the Commander that he must source the funds for the construction of his own seat.
The Golden Company appears to be extremely intrigued by her request and asks to be given a few days to respond. The Commander of the Golden Company appeared sympathetic to her cause in her meeting, but through warging, Sansa comes to learn that they plan to seize her and use her as a pawn in their attempt to crown Daenerys Targaryen. Sansa makes great haste in leaving the city in the company of the Wolf Pack, and a large group of sellswords who are not attached to any company.
On the way over the Narrow Sea, Sansa discovers that Tywin Lannister is dead, and that Tommen and Myrcella, the sole surviving Lannisters, are in the custody of Stannis. Renly, who had captured the children, has been slain by a shade. Robb is betrothed to Margaery Tyrell, and now commands the largest forces of Westeros. Sansa understands that the plot to betray Robb is now unlikely to happen but remains adamant that she must return to the North to keep the Boltons and Freys in check.
Sansa makes landing at White Harbour and, after a period as the guest of the Manderlys, she marches to Winterfell, accompanied by the Wolf Pack, a contingent of Manderly men and the red priests. Within a few days, Sansa arrives at Winterfell and is reunited with Bran and Rickon. Sansa shares her concerns about the Boltons and Freys with Maester Luwin, who is greatly alarmed. He questions her on how she became aware of such a plot but when Sansa attempts to explain, he dismisses it as a fever dream. Luwin orders that Sansa be confined to her bedchambers as he believes her to be hysterical, but Sansa has the support of her own armed men, as well as the Stark guards. Sansa orders Maester Luwin to get the information to Robb with all secrecy.
Luwin informs the Starks that the Greatjoys have been harrying the coast of the North, and have even attempted to attack castles. Sansa orders the Wolf Pack to confront the Ironborn, together with a few of the Stark men. Days later, Sansa and the rest of the Stark household is roused when the loyal Stark guards deliver Theon Greyjoy in chains. Theon had been caught by the guards, together with a contingent of Ironborn, attempting to break into the castle. The guards had brutally beaten him, and Bran orders that he be confined to his former room, under guard.
Sansa is shaken by Theon's betrayal and renews her concerns for Robb. Maester Luwin informs her that he had sent a rider to Robb, who is marching to Highgarden for his wedding to Margaery. Sansa, meanwhile, prepares to guard Robb's flank and writes to the Greyjoys, demanding that they cease all hostilities, as they once more hold Theon hostage.
The Wolf Pack returns to Winterfell, and Sansa invites Kato to a meeting with Luwin and Bran. Having already explained to Luwin and Bran the condition for the support of the Wolf Pack, Sansa believes that the time is ripe for the fulfillment of the agreement. Kato and Luwin pore over a map of the North, and Luwin points out that a new House would be of most strategic importance on the Western coast of the North which is vulnerable to the Ironborn. Sansa, however, believes that the new House should be established in close proximity to the Dreadfort to effectively serve as a counter to the Boltons. Luwin advises against as it could potentially be seen as a sign of mistrust. Sansa relents and Kato is given leave to begin construction of his new seat at Sea Dragon Point. As they discuss the terms, a raven comes from the South. Robb has married Margaery at Highgarden, and Catelyn is making her way home to Winterfell, together with Arya. It is revealed that Arya had essentially delivered the castle, as she had assassinated Tywin herself. Robb reveals that he has received her warning, and that he and the Tyrell's are keeping the Boltons and Freys away from each other, and at arm's length, by giving them dangerous tasks. Further, he reveals that Lady Olenna has proven the strength of her spy network and had managed to discover conclusive evidence of the Bolton's betrayal, and that they are about to make their move. Further, Robb is now preparing to go to war against Stannis, as the Baratheon has refused to acknowledge the secession of Robb's kingdoms, and has no intention of surrendering his claim to the entire seven kingdoms.
Sansa, seeing in Robb's letter an opportunity, informs Kato that it is quite possible that he can save greatly, by becoming the Lord of an already existing Northern seat. Sansa encourages the Wolf Pack to seize the Dreadfort, and to ensure that the Castle is not allowed to communicate with the outside world. Kato and his Company ride out that same day and with the aid of the elephants they have brought over, they are able to seize the castle. Upon finding the state of those held captive there, the Wolf Pack kills most of the inhabitants of the Dreadfort. Kato writes to Sansa relaying all of this and Bran declares him the new Lord of the Dreadfort.
Catelyn, Arya and Brynden Tully arrive at Winterfell, along with thousands of Robb's soldiers, some of whom are returning home to tend to their crops, and will disperse all throughout the North. With the soldiers, comes the news that Roose Bolton, and the few Bolton soldiers who did not surrender, have been put to the sword or allowed to go to the Night's Watch. Roose himself chose death, but many of his soldiers chose serving at the Wall.
Sansa is overjoyed at being reunited with her family, but, like Arya, finds herself chafing under the constant supervision and control of her mother. Sansa attempts to break free from her mother's overbearing nature by encouraging them to embark upon new projects now that House Stark is effectively one of the richest Houses of Westeros. Sansa points out to Catelyn that the Western coast of the North is extremely vulnerable, and that the North has no fleet to speak of. This she argues, greatly hinders trade and communication across Robb's expanded Kingdom. Catelyn is intrigued by the projects that Sansa outlines and tasks Luwin with establishing the logistics.
As official messengers of House Stark, Sansa and Bran travel to House Manderly to negotiate the construction of a Northern fleet.
Sansa and Bran continue on to visit Robb who is now enthroned at Riverrun. The King however is restless as he believes that Riverrun would make a poor capital, and is not fond of his wife;s suggestion of making Highgarden the capital. Sansa suggests rebuilding King's Landing or establishing a capital in a more Central position.
Robb holds a summit where King's Landing once was, with Stannis and Oberyn Martell, as a representative of Dorne. At the Summit, Robb and Stannis butt heads over their own claims of legitimacy with Robb refusing to kneel to Stannis, who he insinuates is a Kinslayer. Stannis is greatly angered by the accusation but does not deny it. However, Stannis refuses to accept Robb's offer of neutrality, and claims he will go to war soon. Oberyn, meanwhile, takes several shots at both of the leaders and argues that their Houses are both complicit in the murders of his sister, and her children. Stannis and Robb both formally apologize to House Martell for their Houses roles in the murder, but Stannis demands that as a bannerman, he must come to his aid and help his rightful liege lord regain his throne. Oberyn remains scornful, however, and claims that there is no throne to reclaim, as not even the Iron Throne survived the fire. The Seven Kingdoms, he asserts, are no more.
Stannis suggests that he may set aside his wife, Selyse Florent, and instead take Arianne Martell to wife to bind Dorne to him. Oberyn and Robb are both sceptical and amused at the possibility. Oberyn refuses to deliver such news to his brother, as he claims it might deliver Doran to an early death. Stannis storms out of the meeting. Robb and Oberyn are able to come to an agreement of Peace and mutual support after Olenna Tyrell, acting against Robb's wishes, has Gregor Clegane's body, as well as that of Tywin Lannister, presented.
Sansa meets Olenna and Margaery Tyrell again, and is happy to discover that Margaery is pregnant. The three women have a very interesting conversation about women and their power, and comment on several women who have been powerful. Sansa proposes that something be done to ensure that women are given better positions in the world, and are afforded more opportunities. To that end, Sansa proposes that females be allowed to inherit if first in the line of succession, and that the Citadel accept female acolytes. Olenna believes that Sansa is a bit radical, but believes that, with the support of herself, Margaery and Robb, her reforms are possible.
After Margaery leaves, Olenna and Sansa have a conversation about the threat that Stannis poses to them. Sansa cautions against any unprovoked aggression to Stannis but Olenna is quick to remind Sansa that the Baratheon King had murdered his own brother with shadow magic, and that nothing would stop him from utilizing a similar method to kill Margaery or Robb. Thus, Olenna demands that Sansa pit her own Red Priests against Melisandre.