Lancelot had been taking Joffrey and the others to learn the Water Dance from Syrio Forel for a few days.
In the beginning, Joffrey was beaten black and blue all over.
He had wanted to use his authority to order a Kingsguard to teach Syrio a lesson.
But Lancelot told him that among the current Kingsguard, apart from Jaime and Barristan, the other five were probably no match for Syrio if he fought seriously.
Joffrey didn't believe it. He called Ser Meryn Trant and ordered him to secretly teach Syrio a lesson.
So, one night, Syrio was ambushed after using the privy.
The attacker wore no armor but covered his face with black cloth. Wielding an iron sword, he struck just as Syrio exited the privy.
If it had been daylight, Syrio might have died, as he was the one being ambushed and his opponent was skilled.
But Meryn Trant had chosen to strike at night, wanting no one to know of the deed.
Night, however, is not the domain of the knight, but of the assassin.
Syrio dodged the incoming strike and immediately drew the apprenticeship gift Lancelot had given him.
Lancelot had melted down the Valyrian steel sword he found in the Dragonpit and reforged it into five rapiers (slender swords).
The original sword had plenty of material, and rapiers didn't require much steel, so Lancelot obtained five Valyrian steel rapiers.
He gave one to Syrio, who liked it immensely and carried it everywhere.
The other four went to Joffrey, Myrcella, Tommen, and Arya.
According to Myrcella, Joffrey had taken his Valyrian steel rapier to show off to King Robert.
King Robert had remarked sourly,
"Joffrey, you have a good brother!"
Then Robert looked at Eddard Stark.
"Ned, how about melting down your family's Ice so we can each have one?"
Eddard Stark flatly refused.
Syrio drew his rapier and attacked the intruder. The two clashed in the darkness. In less time than it takes to drink a cup of tea, Meryn Trant suffered eight wounds.
"Joffrey misled me! Said he was just a mediocre Water Dancer? I'd say his skill ranks first or second among Water Dancers!"
That night, Meryn Trant fled back to the White Sword Tower.
His White Cloak brothers saw his injuries and asked what had happened.
At that moment, Syrio chased him to the tower.
"Could that man be a Kingsguard? No wonder his skill was decent. I had the advantage of a superior weapon and the cover of night, yet he didn't die and managed to escape. Truly a White Knight," Syrio said with a mix of admiration and mockery.
Just then, an old knight walked out of the White Tower. Ser Barristan Selmy. He wore a white cloak and white enameled armor.
"Who are you? Wounding a Kingsguard in the Red Keep is a grave crime!" Ser Barristan asked.
"Kingsguard, yet acting as assassins in the dark? Your martial skills might rival your predecessors, but your honor? Tsk tsk tsk!" Syrio said.
Ser Barristan's old face flushed red with anger.
"Regardless of who you are, you won't leave here today without an explanation!"
As he spoke, three other Kingsguard blocked Syrio's retreat.
And in front of him stood the Lord Commander of the Kingsguard, Ser Barristan Selmy.
In terms of age, Ser Barristan was older than Syrio.
In terms of vigor, Syrio was in his prime, more so than Barristan.
The duel between them was a clash for the ages between a knight and an assassin, witnessed only by a lucky few.
In the end, the tip of Syrio's rapier stopped at Ser Barristan's throat; a slight push would have pierced it, ensuring death.
Meanwhile, Barristan's sword stopped at Syrio's forehead; had he followed through with the strike, he would have sliced off half of Syrio's head, killing him instantly.
It was a stalemate.
At this moment, Jaime and Lancelot arrived at the Sword Tower.
"What are you doing? Master Syrio? Ser Barristan?" Lancelot asked.
"Lancelot, you know him?" Barristan asked. He withdrew his sword but did not sheathe it.
"He is the Water Dance instructor for myself, Arya, and the others. He was once the First Sword to the Sealord of Braavos," Lancelot explained.
"No wonder your skill is so high," Barristan said.
"Ser, you are too modest! In terms of true strength, you are stronger than me! Firstly, you are older; secondly, my weapon is Valyrian steel: a rapier. This was a gift from my good disciple! Lancelot truly is a good student—talented and respectful to his master!" Syrio said.
But Syrio didn't know that Barristan hated being reminded of his age. The old knight huffed coldly, turned, and walked away.
"Did I say something wrong?" Syrio scratched his head.
"Ser Barristan hates people mentioning his age," Lancelot said.
"Also, why are you here?" Lancelot asked.
Syrio recounted the ambush.
"The attacker must have been Meryn Trant; he wasn't on duty tonight!" Jaime Lannister said.
"As for who ordered him, I already know."
Lancelot went to Joffrey's chambers. He was cuddling with several prostitutes, but seeing Lancelot enter, he immediately hid under the covers and shooed the women away.
"Lancelot, what are you doing here? I was just having some fun."
"Joffrey! Did you know Ser Meryn Trant is dead?" Lancelot said, deciding to scare him.
"What? Impossible! He's a Kingsguard! Who could kill him?"
Suddenly, Joffrey remembered he had sent Meryn Trant to kill Syrio.
"Could it be Syrio? It must be Syrio who killed Ser Meryn Trant!"
"Lancelot, Syrio is a killer! We must find him, arrest him, and throw him in the dungeon!" Joffrey said in a panic.
"No need. He's already here!" Lancelot said coldly.
From behind Lancelot walked a short, plainly dressed middle-aged man with an air of detachment.
"Syrio! How are you here! Lancelot, save me!"
Joffrey screamed.
"Sigh, Joff, you disappoint me. If you didn't want to learn the Water Dance, you could have just said so. Why send someone to assassinate Syrio? Now a White Knight is dead! If King Robert finds out, I'm afraid..."
Lancelot trailed off.
Joffrey was terrified, feeling as if he were facing a demon.
If his evil deed caused the death of a Kingsguard, King Robert might strip him of his heir status and put Tommen on the throne instead.
Thinking of this, Joffrey knelt down immediately, apologizing to Syrio and begging Lancelot for a solution.
"I won't do it again! Please save me!"
"Have mercy, save me!"
Seeing his genuine repentance, Lancelot and Syrio exchanged a glance, then burst into laughter.
"Hahaha!"
"Joff, you've been tricked! Ser Meryn Trant isn't dead. He's just injured and recovering in the White Tower," Lancelot said.
"So that's it. What a relief!" Joffrey collapsed onto the carpet like a deflated balloon.