"CAS" Dean yelled after his angel. "CAS I'm coming hold on!"
Diving into the water after Cas he swam as fast as he could trying to get to Castiel's body. The water buffering him, knowing that if he went for air or blinked that he would no longer be able to see him. Knowing that this was the last chance he would get to show his angel how he felt.
His heart pounding he used the last of his strength to reach his angel. Turning him round he could see Cas' eyes were fading. Cas was dying. But his eyes still reached out and met Dean's. His eyes longing for Dean to say something. To do something.
Dean cupped his angels face. Staring deep into his eyes that were longing for something. Dean leaned in and kissed Cas. Not wanting to close his eyes. So that he could see his angels reaction.
Cas had closed his eyes. He was smiling slightly but still able to kiss Dean back. Dean hoped in the name of God that this showed how much he felt for Cas. How much he cared for him and how if he ever came back those feelings would still be there.
Still cupping Cas' face he closed his eyes knowing that this would be the end. Knowing that when he opened his eyes there would be nothing there. Nothing for him to love. Nothing to kiss.
Dean opened his eye and felt his heart rip in two. Cas was gone. The better half of him was gone. Forever? He hoped not. Swimming back to the dock Dean rested his head on the edge. He started weeping. "Cas." He whispered. "Cas, I love you." Closing his eyes he remembered how his angel had been smiling as he had kissed him.
He picked himself up and walked to the waters edge. There washed up by the river's current was Cas' trench coat. Dean picked it up. Folding it and resting his palm on it he softly said. "Stupid son of a bitch." Gazing out onto the river, he sighed, trudging back to the impala and laying the folded trench coat beside him.
Holding back tears he hit play on his tape player. "CARRY ON MY WAYWARD SOOOONNNN THERE'LL BE PEACE WHEN YOU ARE DONE!" the song rang in his ears. This song made him feel close to Cas. Made him feel close to his angel. He hoped that Cas, wherever he was now could hear it too and that he was thinking of him.