Sir Launcelot, King Arthur's noblest Knight is suspected of having an affair with the Queen. Sir Aggravayne and Sir Modred create a plot to abush him and catch him.
I advise you to disperse to your chambers and in the morning lay your charge before the king. I will answer you and prove on my body that Queen Gwenyevere and I are innocent of treason on this night.
Sir Aggravayne and Sir Modred form their plan and lure Sir Launcelot to the Queens room. There they meet him and attempt to capture and kill them. However, Sir Launcelot kills them all except Sir Modred who is merely injured. He takes this as their chance to flee, but the Queen insists on staying.
Sir Launcelot escapes to his castle but later realizes that the Queen is in danger so returns to rescue her and in the process kills two honorable knights in the process. This outraged the King and he immediately marched his army to the castle for the return of his Queen. Both sides suffered losses with no outcome. Later the pope interfered and formed a deal. This lead to the Queen being returned and Sir Launcelot banished.
King Arthur and Sir Gawain are both gone fighting a war and Sir Modred, the prince, takes it upon himself to become the king. He forces the Queen, his mother, to marry him but she flees. When the King hears about this he is outraged and they both rally up their armies and go to war. They fought long and hard and both sides suffered. Sir Gawain is killed and King Arthur is injured. He orders Sir Bedivere to throw his sword into the water, which he finally does the third time and notices an image.
Sir Bedivere repeats what happened to the King and he orders him to take him to the water and put him in the edge. The sword needed to be thrown in the water so it does not end up being used for evil if it were to fall in the wrong hands. King Arthur is put in the water and disappears. The Queen and Sir Launcelot hear of this news and are mortified. This urges the Queen to give up her belongings and repent for all of her sins.
Sir Launcelot wants to be with the Queen but she refuses as it would go against King Arthur. She wants to repent for all her sins and turns him down. Sir Launcelot is heartbroken and becomes a hermit where he lives humbly. The Queen dies later on and once Sir Launcelot hears of this, it leads him to also die. He basically dies of a broken heart.