This is AU but I've tried to keeps CS Lewis's characters "in character". He owns them and Narnia not me. Walden owns the movie.
In this alternative universe, Shasta and Aravis never met up while traveling. Both got delayed on their escape to Tashbaan. As a result, Rabadash succeeded in kidnapping Susan and conquering Archenland.
King Peter led the Narnians through Tashbaan back to the boat. The fair haired king had much on his mind but was trying to concentrate on their surroundings. He knew that despite the safe conduct from the Tiscroc, an "accident" could happen in the city. His advisors had been much more nervous about the ride to and from the palace than anything occurring in the palace before ambassadors. As he rode, the High King swept his gaze to both sides of the road as well as the middle. The Calormene slaves and soldiers, were calling out for people to stand aside for him. There was a murmur from the crowd as they looked at the alien Narnians. Suddenly, Peter saw something that amazed him.
Prince Corin of Archenland – wearing filthy rags – was standing with a horse on the side of the road. The teenage prince was staring at him with wide eyes. Peter called a halt to the party.
Peter called out: "Corin, what are thou doing here?"
The boy did not reply. Lord Peridan who was riding behind Peter, swung down from his horse and walked over to the boy.
"Prince Corin, the High King is speaking to you. How is the name of Aslan did you get here?" asked the loyal knight.
The boy stared at him – first his face was blank than horrified and almost frightened. The boy was holding tight to the reigns of a horse.
"What is the matter with you? Have you gone mute? This is not appropriate behavior for the king's son of Archenland. By whatever means you traveled to Tashbaan, you should not be hanging your head like a slave" declared Lord Peridan.
The boy looked at him in amazement and clung even tighter to the horse reigns.
The High King had ridden over. Peter was most annoyed. He told Peridan to re-mount and told the boy to get on his horse and ride next to Peridan. The boy looked panicked but obeyed without speaking. Peter was mystified. He had the least contact of his siblings with the young Archenland prince but when was Corin ever quiet?
King Peter was relieved when they arrived back at the Splendor Hyaline, the Narnian great ship. The party dismounted. Since the horses and the unicorn were all talking beasts, there were no problems getting them up the gangplank. Neither the centaurs or the talking beasts enjoyed being on a boat but they would all do it to help rescue Queen Susan.
Lady Deidre immediately rushed over to King Peter and Lord Peridan. She motioned for the horse she had ridden to join them.
"Your Majesty, my dear brother, this is Hwin. She was kidnapped from Narnia as a young foal. Isn't it marvelous that we have been able to rescue her as well? Hwin, this is King Peter the High King and my brother Lord Peridan."
Peter smiled saying "Welcome home, Mistress Hwin. When we return to Narnia, we will help you re-unite with your family." The High King placed a hand on the mare's head in greeting.
"Thank you, Sire. I was kidnapped as a young foal and do not have many memories of Narnia but I promise I will be a most loyal subject" said the mare who was awed at speaking with the High King.
A voice nearby spoke up saying "I was also kidnapped as a foal and have spent years in captivity."
Peter and Peridan turned and stared at the horse and the boy standing nearby.
"What is your name? How did you find Prince Corin?" asked King Peter.
The horse replied "I am called Bree, your Majesty. As for my boy, he is no prince but rather a slave. I found him several weeks ago at a fisherman's cottage where my former master had stopped for the night. My boy – his name is Shasta – was clearly Northern stock – and we both wanted to escape so we helped each other. We traveled by night until we reached the city. We had planned to ride across the desert to the North and freedom."
Peter was silent for a moment and then said "Well, you are free now and you are both welcome to journey with us back to Narnia."
The king continued to stare at Shasta and then said "This is a mystery to me, how a boy raised in Calormene captivity could so closely resemble a Prince of Archenland. Do you know anything of your family, Shasta?"
Shasta was nervous. He had never spoken to a king before and other grown-ups were listening. The boy wet his lips and shook his head.
"A Calormen fisherman raised me and I called him father. All I know is that he found me in a boat when I was an infant. A knight was in the boat with me but he was dead when the boat was found" replied Shasta.
Lord Peridan commented "Perhaps when we return to Narnia, we can solve this mystery. The boy appears to be around the same age as Prince Corin and must have been born around the beginning of your reign Sire. Perhaps someone will remember a child being kidnapped."
Peter nodded. He would worry about this mystery later. The next step was to rescue Susan and then leave this accursed city.
At sunset, Peter the High King stood on the deck of the great ship and prepared to wind the horn of Queen Susan. The High King was dressed in a dark leather tunic, black shirt and black leggings with his sword and a dagger at his waist. He wore leather gloves and a black cloak. Daggers were in each of his boots.
As the sound faded, Peter said "It may take a few hours before they arrive. We will have to wait for dark anyways."
Several hours later, Deidre was standing near the railing talking to her brother Peridan. The night was dark with only a sliver of the moon. She and Nola had carefully reviewed all they knew of the palace and the location of Susan's rooms with Peter and Peridan. She was still not clear about their plans. Peridan was dressed similar to the High King for he would be accompanying the king to rescue Susan.
"I would feel so much better if you were wearing your armor" said Deidre.
Peridan shook his head as he replied "It is better to not have the weight and we don't want to risk any clinking or other extra noise. We are hoping we will be able to rescue the queen without a fight but we can handle a few simple fights without armor. We will bring our shields and the leather provides some protection. Don't worry Dee. We will be setting sail for Narnia before daybreak."
Deidre looked up as she heard a sound from above. She heard a murmur of voices as others heard the sounds as well. Peridan gave her a quick hug and said "Be well, sister. I will see you soon. Stand back by the rail." Peridan picked up his shield and slung it on his back.
Lord Peridan walked over to stand next to King Peter. Sallowpad the Raven perched nearby. Peridan picked up some cloth and arranged it around his shoulder like a sling. Peridan then bent down and picked up Cathlin, a black talking cat, and carefully placed her in the sling. Peridan adjusted it so the cat would be safe. Cathlin was a favorite companion of Susan's and Deidre knew the talking cat would do anything to help rescue the young queen. Peter slung a sack over his shoulder with some supplies they might need such as rope.
The deck near them had been cleared. Deidre waited in anticipation and then she saw them – shadows at first and then they were real. Two magnificent horses with wings landed on the deck. Deidre gasped – she had heard of such a beast in old legends from the creation of the world but who alive had ever seen them?
Peter respectfully approached the horses and said "Greetings. Thank you, Flynn and Finlay for responding to the horn. We are most grateful for your help."
Flynn, the older of the two flying horses, replied "Greetings King Peter. We are glad to be of service, good king. Aslan desires us to help in the rescue of your royal sister. Let us be off."
The ride on Flynn's back was one of the most exhilarating experiences that Peter had ever had while in Narnia. The horses circled around the city to gain some height before they approached the palace. The sight of Tashbaan and the desert from the air was unforgettable.
The horses landed on the roof of the old palace on the side near Susan's rooms. At least that is what Peter and Peridan hoped based on Deidre and Nola's information. The two men climbed down from the backs of the winged horses and thanked them. Sallowpad the Raven had followed them and landed near Peter's feet. Peridan carefully removed the sling he was wearing and released Cathlin. As planned, both talking beasts took off to search for the queen. Once they located Susan and scouted the nearby guards they would return.
Nearly an hour passed before Sallowpad returned and declared: "Your Majesty, my lord, we have found the queen. Her Majesty is safe and Cathlin is waiting near the queen's chambers. Come and I will show you the quickest way."
Peter and Peridan walked to the edge of the roof and could see a balcony with a large window. Sallowpad explained that the window led to an empty parlor. Once in the parlor, they only needed to go down a short hall and down a flight of stairs to reach the queen's chambers. The top of the stairs were unguarded but there were four guards were in front of the queen's chambers. The doors were locked but Queen Susan believed that one of the guards had the keys.
Peridan carefully tied rope to a sturdy spire decorating the roof. The two men slid down the rope and landed on the balcony. The window was open. Peter carefully reached through the window and located a vase that Sallowpad warned was on a table in front of the window. Peter placed the vase on the balcony and then climbed through the window followed by Peridan.
Peter shifted his shield to his arm and drew his sword. He then slowly opened the door a crack. As Sallowpad described, there was a short hallway leading to a staircase. The hallway was empty. Peter stepped into the hallway followed by Peridan and Sallowpad and quietly walked to the staircase. At the bottom of the stairs, Peter could see a guard standing with his back to the staircase. There was no way to get down the staircase without being seen.
The King heard a soft hiss and saw Cathlin move out of the shadows. She tilted her elegant head towards the guard and began to walk down the stairs. Peter nodded and waited at the top of the stairs for the talking cat to cause a distraction. Near the bottom of the stairs, Cathlin began to run and let out a howl as she rushed by the guard. The guard, as hoped, looked at the cat and took several steps away from the bottom of the stairs. Peter drew a dagger from his boot and began to quietly walk down the stairs. Peridan was right behind him. They could hear a guard laugh and the sound of a vase being knocked over as Cathlin ran down the hall.
Peter had almost reached the bottom of the stairs when the guard re-appeared looking startled to see the king. Peter threw the dagger slicing the guard's throat. The guard stumbled back and fell against the wall. The other three guards turned pulling out their scimitars as Peter leapt into the hall and swung his sword at the nearest guard. The fight only lasted for a few strokes before the guard was dead. Peridan's fight lasted no longer. The last guard had begun to run down the hall yelling for reinforcements. Cathlin leapt onto his back causing the man to stumble. Peridan quickly caught up to him and dispatched him.
King Peter rushed to the chamber door which was locked and called out "Check the guards for keys."
Peridan checked the body of the guard closest to him and saw he was wearing a key ring with several keys. He grabbed the ring and rushed to the door trying several different keys. The door opened.
Susan was anxiously waiting. Sallowpad had woken Susan earlier; she had dressed quickly and waited. She had heard the sounds of fighting outside her room. The young queen was wearing a flimsy Calormene dress and sandals and her Narnian crown. Peter entered the room, rushed to his sister and gave her a hug.
"I knew thou would come" said Susan hugging her brother.
"Su, does thou have anything warmer than that dress" asked the king.
The young queen shook her head and said "Nay, they took away my Narnian clothes and did not give me anything practical to wear."
Peter quickly took off his own cloak and wrapped it around his sister.
The queen motioned to the corner and a teenage girl stood up. Unlike Susan, she was dressed a bit more practically in Calormene riding clothes. Peter and Peridan both looked startled.
Susan said "This is Aravis. She has become my friend and I want to help her to escape to Narnia. She is coming with us."
Peter replied "Sister, I am not sure that is wise."
"We don't have time to argue about it, we should probably leave and Aravis is coming. I won't leave her behind to marry that awful Ahoshta" replied Susan.
Peridan was in the doorway and said "Sire, I hear men coming down the hall. The alarm must have been raised. We should go quickly."
Peter said "Let us go then. Cathlin lead the queen and Lady Aravis to the balcony. Run quickly sister and take this with you. When you get out to the balcony, wind your horn." He pressed the horn into Susan's hand.
Susan and Aravis ran up the stairs following Cathlin. Sallowpad was at the end of the hall and called out "There are five guards heading this way, Sire."
Peter and Peridan ran up the stairs and turned at the top. Guards began running up the stairs behind them. Peter and Peridan both threw daggers stopping the guards at the front. Two other guards stumbled backwards as the dead bodies tumbled down the stairs. One guard lunged over the bodies and lifted his scimitar. It only took three strokes for Peter to disarm him and quickly kill him.
Peter and Peridan turned and ran towards the parlor. Once in the parlor, they moved a couch against the door, hoping that would slow the pursuit of the remaining guards. Peter could hear the sound of Susan's horn and a moment later the beating of wings. He and Peridan climbed out the window.
The balcony was not very large so only one horse could land at a time. Flynn landed first and Peter climbed up with Susan behind him. Sallowpad flew down – the wise raven had flown to the top roof and retrieved the sling that Peridan had used to carry Cathlin. Peridan hastily put on the sling and put Cathlin in the sling. He heard a crash as the guards rushed into the room. Flynn took off and Finlay landed on the balcony. Peridan mounted and reached down a hand to help Aravis. Finlay took off as a bewildered Calormen guard climbed out onto the balcony.
As Peter had instructed, the Spendour Hyaline had already set sail for Narnia. The flying horses flew along the river leading to the ocean until they located the grand ship. The horses landed on the deck of the moving ship. Peter swung down and helped down Susan. There was the sound of shouting and cheering as the Narnians saw their beautiful queen. Deidre and Nola rushed to embrace Susan.
Peter thanked the flying horses for their help and asked if they would see the horses again. Finlay and Flynn shrugged their magnificent shoulders.
Flynn said "Since the days of our ancestor Fledge, we have assisted sons of Adam when requested by Aslan. If needed, we will fly out from the west again. May the remaining days of your reign be blest High King of Narnia."
The two horses flew off into the evening sky.