"We aren't needed here anymore." As Peter said these words, he removed the sword and sheath from his belt and held it out to Caspian.
"I will look after it until you return," Caspian declared, gazing into Peter's earnest eyes as he took the sword from his hand.
Peter saw the desperate question in Caspian's beautiful face: You are coming back, aren't you? It broke Peter's heart to know that he had to disappoint him, but Susan dropped the bomb before he could. She had seen the look on Peter's face; perhaps she knew how much this goodbye would hurt him.
"I'm afraid that's just it," she said apologetically. "We aren't coming back." She looked over at Lucy and Edmund. They both looked scandalized. "At least, Peter and I aren't." The two youngest looked to Aslan, their faces full of questions.
"They have learned what they had to learn from this world," Aslan told them. "Now it's time that they learn from their own."
Peter held Caspian's gaze, noticing that the fiery, passionate determination that always rested in his eyes had gone; now Caspian looked back at Peter with a mix of sorrow and confusion in his expression. It almost scared Peter to see him look so lost. "I am sorry we could not spend more time together," Caspian said. "You have been a great friend to me, Peter."
Peter smiled sadly. "I'm sorry, too," he replied. "But thank you, for everything you've done."
With a bit of the fervor back in his eyes, Caspian nodded, and smiled back. "I will never forget you," he promised. They stepped forward and embraced, dreading the moment Peter walked through the door to his world because it meant they would not see each other again. When they let go, both had tears in their eyes. They looked at each other once more, saying the same things in their faces that they would never be able to express correctly: the gratitude they had felt ever since Caspian attacked Peter in the forest (for if he had not done so, they would have had a much smaller chance of defeating Miraz), and for the friendship they had developed during Peter's visit to Narnia.
"I love you, you know," whispered Caspian; in a voice so quiet that only Peter could hear. "I did ever since the single combat… There was just a feeling I knew I had never experienced." There was sadness clear in everything about him: his eyes, his voice, the way he stood, and the small smile that Peter noticed had always been ever-present on Caspian's face whenever they looked at each other.
Peter blinked back the tears that now threatened to fall. He knew he had to be strong, but it was so hard. "I love you too, Caspian," he confessed for the first time, to Caspian and to himself. He really did love Caspian, and he had known it for a long time… perhaps he just hadn't wanted to admit it.
They looked at each other again, for just a few magical moments, and then Peter turned and walked to where his siblings stood waiting. They gazed out to the crowd of Telmarines before walking through the hole in the tree trunk, and finding themselves in the train station in England once more.
Peter knew he would never forget the King who changed his life, as well as saving it. As a couple tears slid down his cheeks, he thought of the face that would be etched into his mind forever. King Caspian, back in Narnia, was thinking and doing the exact same thing.
Somehow, by some connection, they both knew. And by that same connection, they repeated in their minds over and over: I will never forget.