The Trial of Seven in 'A Knight of the Seven Kingdoms' nearly kills Dunk. Here's how he actually dies in the books.

• In "A Knight of the Seven Kingdoms," Dunk risks his life to protect a girl from Aerion Targaryen.
• In episode five, he fights for his life against Aerion and six other knights in a trial by combat.
• In the books, the deadly Trial of Seven changes the trajectory of Dunk and Egg's lives.

Spoilers ahead for "A Knight of the Seven Kingdoms" season one, episode five, "In the Name of the Mother," and the book "The World of Ice & Fire."

In Sunday's episode of "A Knight of the Seven Kingdoms," the show's humble hero Dunk faces off against the merciless Prince Aerion Targaryen in an ancient ritual known as a Trial of Seven.

In a previous episode, Dunk risked his life to protect an innocent girl from Aerion's violent outburst. Dunk is saved by Egg, his squire who's also secretly a Targaryen prince, and taken into custody — but he's still not safe from the dragon's wrath. Aerion wants Dunk punished for punching and kicking a prince. The standard penalty would be to cut off his hand and foot.

In a desperate attempt to save his skin, Dunk demands a trial by combat. In the world of Westeros, this demand is sacred and cannot be refused; it's believed that the gods will punish the guilty party on the battlefield.

But Aerion ups the stakes. He insists instead on a rare, seven-versus-seven melée-style trial. (The Faith in Westeros says there are seven gods, so the idea is to enlist a different champion for each one.)

It's a cruel twist. Aerion knows that Dunk, a lowly orphan with no allies or wealth, is unlikely to find six other knights to fight for his cause.

Thankfully, an impressive group does come to Dunk's aid, including Ser Lyonel Baratheon (ancestor of Robert, Stannis, and Renly from the main series), and even Prince Baelor Targaryen, Egg's uncle and heir to the Iron Throne. Thus, Dunk's foolish chivalry brings about the first Trial of Seven in a century.

"A Knight of the Seven Kingdoms" showrunner Ira Parker told Business Insider that the fateful showdown was at risk of being cut down and simplified due to the show's relatively small budget compared to other "Game of Thrones" series. But Parker said he stood his ground with HBO to ensure the scene matched the description in the source material, George R. R. Martin's novella "The Hedge Knight."

"We have major, major budgetary constraints on this show," Parker said. "So you're going to get pressure to turn a Trial of Seven into a Trial of Five very quickly. And obviously, canonically, these things have to be well represented."

Parker's stubbornness pays off in episode five, titled "In the Name of the Mother." The battle is a brutal, gory spectacle that feels as grave and urgent as any high-budget "Game of Thrones" sequence.

"We wanted to, where we could, blow people away. Because we do a very small story. This is a little quieter," Parker said. "And so where we had an opportunity to go big, we wanted that to feel rich, and like 'Game of Thrones' of old."

Although Dunk takes a gruesome beating, he eventually overpowers Aerion using brute strength. The prince yields before Dunk kills him — but the battle still proves fatal. Three knights die, including Baelor, which ends up having serious consequences for Dunk, Egg, and the entire realm.

Keep reading to learn how the Trial of Seven affects the duo's future and Dunk's fate in the books.

In the books, Dunk becomes Lord Commander of the Kingsguard under Aegon the Unlikely

Baelor was the firstborn son of the king, so his untimely death changed the line of succession. He was also a war hero loved by the common folk, so his death was a double blow to the realm's morale.

It turns out that Baelor's fate was only the first of a series of tragedies for House Targaryen — a dark omen of the dynasty's downfall.

Martin's fictional history book about Westeros, "The World of Ice & Fire," reveals that after the Trial of Seven, royal heirs began dying at an alarming rate from disease, suicide, random accidents, or, in Aerion's case, a classic case of Targaryen Madness. The prince died after drinking wildfire, thinking it would transform him into a literal dragon.

Before long, Egg's father became King Maekar. Only Egg and his older brother, Aemon, were left to succeed him — but Aemon had long ago surrendered his royal title to become a maester.

That left Egg as heir to the Iron Throne after his father's death. He became known as Aegon the Unlikely, and he enlisted Dunk as the Lord Commander of his Kingsguard.

Because Egg spent his childhood as Dunk's squire, traveling the Seven Kingdoms and interacting with peasants, he was a compassionate ruler. He introduced new laws to uplift the smallfolk, giving them new rights and protections. However, this provoked "fierce opposition and sometimes even defiance amongst the lords," according to "The World of Ice & Fire."

Over time, Egg became convinced that the only way to unite the Seven Kingdoms was to reverse the extinction of the dragons — solidifying his family's power and deterring rebellion.

Egg's reign ultimately ended in a mysterious fire at Summerhall, a small castle belonging to House Targaryen. The king had gathered his family there to celebrate his granddaughter's pregnancy.

Nobody knows exactly what caused the fire to burn out of control, and the history book is intentionally vague about the tragedy: "Summerhall left very few witnesses alive, and those who survived would not speak of it," it reads. The book doesn't name victims, either, but it's heavily implied that both Dunk and Egg — plus Egg's eldest son, Duncan — died in the flames. This lore was confirmed by Martin's "A World of Ice and Fire" app, an official companion guide to the series.

The prevailing theory is that Egg started the fire in a failed attempt to hatch dragon eggs. Some fans even believe that Egg intended to kill himself and his descendants in a blood-magic sacrifice. After all, it's often said in "Game of Thrones" that "only death can pay for life," and there is a special kind of power in a king's blood.

"My brothers dreamed of dragons," Maester Aemon says in the original book series. "And the dreams killed them, every one."

It's likely that Egg's wife, his sisters, and his brothers' children died at Summerhall too. But Egg's granddaughter, Princess Rhaella, miraculously survived.

As the castle burned, Rhaella gave birth to Prince Rhaegar — the eldest brother of Daenerys and, as we discover in "Game of Thrones," the secret father of Jon Snow. In "The World of Ice & Fire," it's implied that Rhaella would've died at Summerhall "but for the valor of the Lord Commander." Many fans theorize that Dunk carried the princess to safety.

Despite the tragedy of Summerhall, the event spelled a heroic end to the story of a once-hated hedge knight.

After the Trial of Seven, Dunk is blamed for the loss of a future king. Dunk also blames himself, but he tries to find comfort in the unknown. "If I had not fought, you would have had my hand off. And my foot," he says in "The Hedge Knight" to Baelor's brother, Maekar. "Well, mighten it be that some morrow will come when I'll have need of that foot? When the realm will need that foot, even more than a prince's life?"

Maekar replies, "It's not bloody likely." But oddly enough, Dunk is probably right. Most book readers believe that either Daenerys or Jon is the prophesied hero Azor Ahai, destined to save Westeros from the White Walkers. Both were born of Rhaella's line. Without Dunk and his feet, the princess may have died along with her unborn child, and "Game of Thrones" would never have happened.

But what if Westerosi historians didn't know Dunk's entire life story? Dexter Sol Ansell, who plays Egg in "A Knight of the Seven Kingdoms," recently stated that Dunk didn't actually die at Summerhall, as readers had long thought.

"We know from George," Ansell said during an on-camera interview with Decider. "We know Dunk survives, but we don't know if Egg survives."

"We don't know if that is exactly what happened," Peter Claffey, who plays Dunk, interjects. "Let's just get this season one out of the way and we'll see."

Representatives for HBO, Ansell, and Martin didn't respond to Business Insider's requests for comment about Dunk's true fate.