|Although this article is based on canonical information, the actual name of this subject is pure conjecture.
The assassination of Daenerys Targaryen is a pivotal and closing event of Daenerys Targaryen's war for Westeros. Following Daenerys Targaryen's destruction of a surrendered King's Landing, in which hundreds of thousands of innocents were slaughtered, Jon Snow reluctantly kills his lover, aunt, and queen, Daenerys, to prevent more massacres and destruction in Daenerys's quest to 'liberate' the world.
Daenerys, who gradually succumbed to the Targaryen madness, initially agreed to Tyrion's proposal that they give the people of King's Landing a chance to surrender. However, at the Battle of King's Landing, she burned down the city even after the Lannister soldiers surrendered. King's Landing was left in ruins from the dragonfire of Drogon and the wildfire caches placed beneath the city by Daenerys's father. Thousands of smallfolk and surrendered soldiers died. Cersei, Jaime, and Euron all died as well, and Daenerys took control over the ruined city.
Jon, Davos, and Tyrion walked through the city in the aftermath, stunned and dismayed by the amount of destruction and death caused by their well-intentioned queen. Daenerys delivers a speech to her Dothraki and Unsullied forces, declaring the sack of King's Landing a success. Daenerys tells them all that they "liberated" King's Landing, "You tore down their stone houses, you gave me the Seven Kingdoms." She declares their war is not over, proclaims her intention to conquer the world and put an end to the rule of all tyrants, breaking the wheel for good. Before them all, Tyrion disgustedly confronts Daenerys for slaughtering an entire city; he is subsequently arrested by Daenerys.
Jon visits Tyrion, who warns the former about what Daenerys has become. As Jon struggles with this, Tyrion reasons, "I know you love her. I love her too, not as successfully as you, but I believed in her with all my heart. Love is more powerful than reason." Jon reflects, "Love is the death of duty." Tyrion tells Jon that he is the shield that guards the realms of men, who tries to protect people, "Who is the greatest threat to the people now?" Tyrion acknowledges he is asking Jon to do a terrible thing, "But it is also the right thing." Due to his love for Daenerys, Jon doesn't think he can do it. Tyrion reminds Jon that his sisters will never kneel for Daenerys.
In the ruins of the throne room, Daenerys approaches the Iron Throne, reaching out to touch it when she is found by Jon, who confronts her over burning down King's Landing, killing thousands of men, women, and children, and executing surrendered Lannister prisoners. Daenerys defends that these actions were necessary and Cersei mistakenly thought mercy was her weakness. Jon pleads with Daenerys to forgive Tyrion and all of the people of King's Landing, to make them see they are mistaken about her. Daenerys defends her actions and explains she can't hide behind small mercies, "The world we need won't be built by men loyal to the world we have." Jon says they need a world of mercy but Daenerys believes her actions are the way they build a good world. Distressed, Jon asks Daenerys how she knows it's good and questions, "What about everybody else? All the people who think they know what's good?" Daenerys simply responds, "They don't get to choose." Embracing Jon, Daenerys asks him to be by her side and to build her new world together. As the two kiss, a greatly anguished Jon tells Daenerys that she will be his queen forever before he stabs her in her heart with his dagger, catching her as she falls.
Weeping, Jon holds Daenerys in his arms as she dies. While he cradles her body, Drogon flies into the throne room. As Jon prepares to face death via Drogon's flames, Drogon roars in anger and grief and unleashes his fire across the throne room, melting the Iron Throne. He does not kill Jon, but instead picks up Daenerys's corpse and flies away, leaving a grieving Jon behind.
Jon Snow is taken prisoner by Grey Worm and the Unsullied for killing Queen Daenerys. Some time later, Tyrion Lannister is brought before a gathering of the great Westerosi lords and ladies in the Dragonpit by Grey Worm to decide his and Jon's fate. Among the nobles are Sansa Stark, Bran Stark, Arya Stark, Davos Seaworth, Brienne of Tarth, Yara Greyjoy, Gendry Baratheon, Robin Arryn, Yohn Royce, Edmure Tully, Samwell Tarly, and the unnamed Martell. Daenerys's loyalists, including Yara and Grey Worm, want Jon executed for killing Daenerys, while Sansa and Arya threaten if Jon is harmed, the Northern army will destroy them in retaliation. Tyrion proposes that they leave it for the new king or queen to decide their fates, and suggests that the gathered leaders choose the next king or queen. On Tyrion's prompting, Bran is chosen as king, and Tyrion declares that from now on, the king will be chosen by a gathering of the lords and ladies instead of inheriting the crown, which, in some ways, "breaks the wheel" that Daenerys intended - that of hereditary rule. The new King Bran names Tyrion his Hand of the King and agrees to allow the North to be independent under his sister Sansa, reorganizing the Seven Kingdoms into the Six Kingdoms.
Later, Tyrion informs Jon that he'll be sent to the Night's Watch, satisfying Grey Worm and the Unsullied, who leave Westeros for the Isle of Naath. Jon bleakly wonders if he did the right thing, that it doesn't feel right. Tyrion says to ask him again in ten years. They bid each other farewell for now.
As Jon leaves King's Landing for the Night's Watch, he says his goodbyes to Sansa, Arya, and Bran. They exchange emotional embraces. Jon turns to Bran and kneels, "Your Grace, I'm sorry I wasn't there where you needed me." Bran responds, "You were there exactly where you needed to be."
In the books
In the A Song of Ice and Fire novels, an equivalent event has not occurred. The TV show has surpassed the timeline of the books, two of which are yet to be published, so it is unclear if such an event will occur.
- The death of Daenerys has been foreshadowed in "Valar Morghulis", in which she experienced a vision in Qarth of the throne room surrounded by what seems to be snow (actually, it turned to be ashes) and ruins she would eventually cause, followed by a reunion with her deceased husband and son in the 'afterlife'.