The 1953 film "Knights of the Round Table" is loosely based on on the 1485 book Le Morte D'Arthur by Sir Thomas Malory about the legendary early medieval British King Arthur, his wife Guinevere, his knight Lancelot, and other characters. The film's setting has been moved to the late middle ages with knights wearing armor and engaging in tournaments. Lancelot and Guinevere are chaste lovers and Lancelot gives her a large gold coin which she keeps. Her husband sees her with the coin and becomes suspicious that she is having an affair. The coin is shown but not in close-up, it appears to be the size of an American silver dollar or British crown.

Merlin (Felix Aylmer) is not a wizard but a counselor to Arthur Pendragon (Mel Ferrer), one of the claimants to be the king of England. Another claimant is Morgan Le Fay (Anne Crawford), Arthur's half-sister, and her boyfriend Modred (Stanley Baker). A meeting is held to decide the issue. Merlin explains that the rightful king can remove a special sword named "Excalibur" from an anvil.

Modred fails to pull the sword out and Arthur gives it a try.

Merlin explains that Arthur is not yet king and must prove himself in battle. Both Arthur and Modred have armies of knights and soldiers.

Arthur and his officers meet Modred, Morgan, and their people.

Arthur is wearing a knight's armor and a helmet with an image of the "Holy Grail", the cup which Jesus Christ drank from at the Biblical Last Supper and which has become a holy relic and an object of quests by knights.

The meeting does not bring peace or a decision and a battle follows which is won by Arthur's forces. Morgan and Modred promise not to cause any more trouble and join Arthur's court. Sir Lancelot (Robert Taylor) has been riding around and meets the Green Knight (Niall MacGinnis) at a castle. The Green Knight informs Lancelot that he is holding a woman captive. Lancelot and the knight have a short fight and Lancelot spares the knight's life.
Lancelot then rides off with the woman who is Guinevere (Ava Gardner) and who informs him that she is engaged to Arthur.

After the wedding King Arthur establishes the famous "Round Table" of twelve knights.

A young knight, Percival, is a member and his sister Elaine marries Lancelot. Percival claims that a voice has ordered him to search for the Holy Grail. Lancelot and Guinevere have formed a relationship and Lancelot gives her a large gold coin.

The coin appears to be the size of an American silver dollar or British crown.
Later Guinevere handles the coin and remembers Lancelot.

The coin appears to have a head of a man on it. Morgan and Modred watch Guinevere handling the coin and feel that her actions can help them break up Arthur's marriage.

Arthur sees Guinevere handling the coin.

Arthur asks her who gave her the coin and she replies Lancelot. King Arthur hosts a tournament of knightly games and competitions.

Lancelot participates and wins his matches. Later in his room Guinevere visits him.

Lancelot asks Guinevere not to visit him but then changes his mind.

At court Morgan and Modred publicly accuse Lancelot and Guinevere of having an affair. The penalty under the law is execution for both participants.

Lancelot apoligises for seeing Guinevere but denies having intimate relations with her.
King Arthur orders that Lancelot be banished from England and sends Guinevere to a convent of nuns. Modred complains about the death sentences not being carried out and leaves. Later he brings his army to meet Arthur's army and the two hold a meeting. A herald announces that if any knight draws his sword the meeting is over and the battle will begin.

A knight sees the snake and pulls out his sword.
The snake appears to be some kind of non-venomous snake similar to a gopher snake. The battle is fought between Modred's forces and Arthur's forces and Arthur is mortally wounded.

Arthur pardons Lancelot and Guinevere and tells Lancelot to throw away Arthur's sword and to kill Modred.

The two men fight, Lancelot kills Modred and then falls into a pool of quicksand.

Lancelot's horse "Beric" rescues him from the quicksand. With the death of King Arthur the Round Table has been closed. Lancelot and Percival visit the room.

Percival hears the Grail voice and tells Lancelot who believes that he has not qualified to see the Grail as he has not lived a "holy life".

Robert Taylor as Sir Lancelot
Ava Gardner as Guinevere
Mel Ferrer as Arthur Pendragon
Felix Aylmer as Merlin
Anne Crawford as Morgan Le Fay
Stanley Baker as Modred
Niall MacGinnis as Green Knight
Director: Richard Thorpe
Writers: Talbot Jennings, Jan Lustig, Noel Langley