Unknown to the Queen, Cardinal Richelieu was soon to know about her secret meeting with Buckingham. The news was brought to him by the Comte de Rochefort, the very man who had so annoyed D'Artagnan at Meung. An agent of the Cardinal, he had placed a spy in the Queen's household.

"The Queen and Buckingham have met," he told the Cardinal. "He has already left for England."

"Then our plan has failed," said the Cardinal, angrily.

"The Queen gave Buckingham a gift," Rochefort went on. "It was a box containing the twelve diamond studs the King gave her on her birthday."

"Well, well!" The Cardinal smiled suddenly. "All is not lost."

He st down and wrote a letter. Closing it with his seal, he sent for a servant.

"Take this at once to London," he ordered.

"Stop for no one."

The letter said:

"Milady de Winter—be at the first Ball Buckingham attends. He will wear on his doublet twelve diamond studs. Cut off two of these. As soon as you have them, inform me."

King Louis XIII was next to know about Buckingham's visit, for the Cardinal told him himself. The King demanded to know why Buckingham had come.

"No doubt to conspire with your enemies," replied the Cardinal.

"He came to see the Queen!" insisted the King, furiously.

"I am unwilling to think so," said the Cardinal. He knew how suspicious the King was of his wife. "But I have heard she cried this morning, and spent the day writing letters."

"I must have these letters!" cried the King.

He immediately sent the Chancellor to search the Queen's rooms, but the only letters he found were to the Queen's own brother. They attacked the Cardinal's power in France, but did not mention Buckingham. The King was delighted.

"I was wrong, Cardinal," he admitted. "The Queen is true to me."

The Cardinal bowed his head.

"Perhaps you should do something to please her, sire. Give a Ball. The Queen loves dancing. It would be a chance for her to wear those beautiful diamonds you gave her for her birthday."

The Queen was surprised and happy when the King told her about the Ball. She asked eagerly when it was to be held. The King told her the Cardinal would arrange everything. Every day for more than a week, however, the Cardinal made some excuse for not setting the date.

On the eighth day he received a letter from Milady de Winter in London. It read: "I have them. Please send money and I will bring them to Paris."

The Cardinal knew that Milady could be there in ten to twelve days. Content that his plans were going well, he spoke to the King about the Ball.

"Today is September 20th. I have arranged that the Ball will take place in the Hôtel de Ville on October 3rd. And do not forget, sire, to remind the Queen to wear the diamond studs!"

The Queen was delighted when Louis told her the Ball would soon take place. But her delight soon turned to shock.

"I wish you to appear in your most beautiful gown," he told her, "wearing the diamond studs I gave you for your birthday."

The Queen stared at the King.

"When is the Ball?" she asked faintly.

"The Cardinal has arranged it for October 3rd," replied the King. At the sound of that name, Queen Anne grew pale.

"Was it also his idea that I should wear the diamond studs?"

"What if it was?" demanded the King. "Do I ask too much?"

The Queen shook her head. "No, sire."

"Then you will appear as I ask?"

"Yes, sire."

Once the King had gone, Queen Anne sank into a chair in despair.

"I am lost," she murmured. "The Cardinal must know everything. What am I to do?"

And she began to weep.

"Don't cry, your Majesty."

The Queen turned sharply around, for she thought she was alone. It was Constance Bonacieux, who had heard everything.

"Don't be afraid," she told the Queen. "We will get those diamonds back in time for the Ball!"

Constance Bonacieux knew her husband would not help. The Cardinal had released him, and given him money. He was now a Cardinal's man. There was one person who could help—D'Artagnan. She told him what had happened, first swearing him to secrecy.

"I will go to London at once," he told her.

Realising not a moment was to be lost, D'Artagnan went to see Monsieur de Treville. He asked if he could arrange leave of absence for him.

"I must go to London," he explained. "I am on a secret mission for the Queen."

Monsieur de Treville looked sharply at the eager young man.

"Will anyone try to prevent you?"

"The Cardinal would if he knew," D'Artagnan admitted.

"Then you must not go alone," said Monsieur de Treville. "Athos, Porthos and Aramis will go with you. Then surely one of you at least will get through to London."

"Thank you," D'Artagnan said, gratefully.

Athos, Porthos and Aramis were as excited as D'Artagnan himself when he explained their mission.

The four adventurers left Paris at two o'clock in the morning. As long as it remained dark, they kept silent. In spite of themselves, they expected ambushes on every side. With the sunrise, their spirits rose.

All went well until they arrived at Chantilly, early in the morning. They stopped at an inn for breakfast. After the meal, the first sign of danger appeared. A stranger who had shared their table called on Porthos to drink the Cardinal's health. Porthos agreed, if the other would then drink the health of the King. The stranger cried that he would drink to no one but the Cardinal. A bitter argument followed. Leaving Porthos to settle it, the others hurried on their way.

They had travelled for several hours when they came upon men mending the road. As they drew level, the workmen drew out concealed muskets.

"It's an ambush!" cried D'Artagnan. "Ride on!"

They spurred their horses forward, but Aramis was wounded in the shoulder. He was able to travel only a little further. Athos and D'Artagnan had to leave him to be looked after at a village inn.

Only D'Artagnan and Athos were left. They rode on. At nightfall they took a room at Amiens. The night passed quietly enough, but when Athos went to pay the bill in the morning, the landlord accused him of using forged money. Four armed men rushed in. They had obviously been waiting.

"Ride on, D'Artagnan!" shouted Athos, drawing his sword.

D'Artagnan did not need to be told twice. He galloped on. At length, his horse exhausted, he reached Calais, the port for ships bound for England. He ran on to the quay. There, a travel-weary gentleman was telling a ship's captain that he must go to England. The ship was ready to sail, the captain explained, but the Cardinal had just issued an order. No ship was to leave without his permission.

"I already have it," the gentleman said, showing a paper. "Will you take me?"

The captain agreed, but insisted that the pass had to be signed by the Port Governor. Hearing this, D'Artagnan hurried away and waited amongst some trees for the gentleman to come back with the signed pass. He had to have the Cardinal's pass. Naturally, the man refused to give it up, and D'Artagnan had to fight him for it. They fought fiercely for some time before the man at last gave in and handed over the precious piece of paper.

Breathing hard, D'Artagnan thrust the pass into his pocket and went to find a ship to take him to England.

The ship D'Artagnan chose had scarcely left harbour when a cannon boomed out. The port had been closed. He had only just been in time. Worn out, D'Artagnan slept while the ship sailed across the Channel. In the morning, he watched eagerly while the vessel dropped anchor in Dover. Soon he was on his way to London.

The young Frenchman knew no English, but he had the Duke of Buckingham's name written on a piece of paper. He was soon directed to the Duke's home, for everyone in London knew him. When he heard that D'Artagnan had come, the Duke saw him at once. He remembered him from their meeting in the dark streets of Paris.

His face became grave when D'Artagnan told him of the Queen's danger.

"We must return the diamond studs to her. Louis must not find out she gave them to me!" he exclaimed. He unlocked the box in which they lay, with a key from a chain he wore round his neck. As he lifted the diamonds out, he gave a startle cry.

"Two of them are missing!"

"Can you have lost them, my lord?" D'Artagnan asked anxiously.

"They have been stolen," the Duke replied grimly. He showed D'Artagnan where the ribbon holding the two missing studs had been cut.

"Wait!" said the Duke. "I remember now. I wore them only once, at a Ball in London. Milady de Winter was there. She has never liked me, but she was unusually friendly. I wondered why. She must have taken them. She must be an agent of the Cardinal."

He paced up and down, thinking. The Ball, D'Artagnan told him, was in five days' time. If Queen Anne appeared with two of the diamond studs missing, the King's anger would e terrible. The Cardinal would have succeeded. The Duke stopped suddenly and turned to the young Frenchman.

"Five days—that's all the time we need!" he exclaimed. "I know what we must do."

Buckingham sent for his secretary, and issued an immediate order. No ships were to sail for France, for he believed Milady de Winter was still in London. Such was his importance in the government that the order was carried out without question.

Next the Duke called for his jeweller, and showed him the set of diamond studs. He promised the man he would pay him well to make two studs exactly like them. They must be finished within two days, and made so that no one could tell the new from the old. The jeweller agreed, and hurried away to start work.

"We are not beaten, D'Artagnan!" cried the Duke.

Two days later the new studs were ready. The Duke and D'Artagnan examined them carefully. They had been so well made it was impossible to tell they were not part of the original set. Now D'Artagnan could leave for France.

As his ship left Dover, he thought he saw Milady de Winter aboard one of the vessels which had not been allowed to leave port. His ship passed so quickly he had little more than a glimpse of her. Once across the Channel he set off for Paris as fast as he could.

Paris was full of talk about the Ball, at which the King and Queen would lead the dancing. More than a week had been spent in preparing the Hôtel de Ville, with flowers and hundreds of candles. The King arrived to the cheers of the watching crowds. Soon afterwards the Queen also entered the ballroom. The Cardinal watched from behind a curtain. A smile of triumph came to his lips. She was not wearing the diamond studs. He was quick to point this out to the King.

"Madame, why are you not wearing the diamond studs?" the King demanded.

The Queen looked round, and saw the Cardinal.

"Sire, I was afraid they would be damaged in this crowd. I will send for them."

While the Queen waited with her ladies in a side room, the Cardinal gave the King the box containing the two studs Milady de Winter had stolen from Buckingham.

"Ask the Queen where these two diamond studs have come from," he suggested.

His triumph turned to rage when the Queen re-appeared, proudly wearing the set of diamond studs. All twelve were there!

"What does this mean?" the King asked, puzzled, pointing to the two the Cardinal had given him. The Cardinal thought quickly.

"I wished her Majesty to have them as a present. Not daring to offer them myself, I adopted this plan."

"I must thank you, your Eminence," said the Queen. Her smile showed she had understood the Cardinal's plot. "I am sure these two must have cost you as much as all the others cost the King."

D'Artagnan had watched the Queen's triumph over the Cardinal. Apart from the King, the Cardinal and the Queen herself, he was the only one in the crowded ballroom who had understood what was happening.

Later, the Queen sent for him. She thanked him, and gave him a diamond ring. D'Artagnan put it on and returned to the gaiety of the Ball. He was well content. He was in favour with the King and Monsieur de Treville, and had helped his Queen when she most needed it. Above all, he had gained the friendship of three brave men, Athos, Porthos and Aramis. One day, he too would be a Musketeer, just like them.

(The End)