Cain and Dean sat in the living room of Cain's house. It looked as Dean remembered it from his first time there.

"I made you a promise. I'm gonna keep it. But I have an idea."

Cain raised his eyebrow but made no comment.

"I'm going to give the Mark back to you. And then I'm going to kill you, and kill the Mark with you. It can't hurt anyone anymore."

Cain stood up, rage in his face.

"Don't you think I haven't tried that already, boy? It won't work."

"Why not?" Dean demanded. "You were going to kill me back in the barn. What would have happened then? You and I are the only ones to ever carry this curse. If one of us kills the other, it should cancel out the curse's effect and destroy it forever!"

Just then, Castiel burst into the house. Cain and Dean both turned to face him.

"Cain!" Castiel yelled angrily, taking huge steps across the room with the angel blade raised.

"Cas, no!" Dean shouted, stepping in front of Cain.

"Dean, he-"

"I let him go. Back at the barn, I let him go. It's okay, Cas, I can explain."

"Dean, I cannot believe you!" Cas rounded on him. "Of all the irresponsible, idiotic things you could have done-"

"I'm here to finish the Mark, Cas. Once and for all. I never wanted you and Sam to use the Book of the Damned, it was an awful idea from the start. It got Charlie killed. Whatever it could have done for me would have been done at the expense of Charlie's life!"

Cain looked back and forth at the two of them.

"The Book of the Damned? Don't tell me you fools have been meddling with that thing. Had you tried to cure Dean using that, it would have unleashed all the Darkness in the universe. The Darkness that God Himself fought before he made the earth."

Cas and Dean exchanged a look.

"Well, good thing I'm not getting rid of the Mark that way, right? What a load of shit that would have been," Dean said breezily.

"Yes, that would have been a huge distraction from all of our other problems, like hunting down Metatron and restoring the rest of the angels to Heaven," Cas agreed. Then he frowned. "What is your plan for getting rid of the Mark then, Dean?"

Sam got out of his car, and walked to the warehouse entrance where Crowley was waiting with two items wrapped in cloth. Sam nodded his head at Crowley, and then walked inside. Rowena sat at her table as usual. She looked up in disgust as Crowley walked in. He returned her look with one of pure hatred.

"Still their bitch I see," Rowena said as way of greeting.

"Mother, as I am not the one tied up right now, I'd say you have that honor," Crowley drawled.

He dumped the two clothed packages on the table unceremoniously.

Rowena unwrapped the first one. Sam stared at the Forbidden Fruit.

"I thought it was an apple," he said thoughtfully.

"Mistranslation," Crowley informed him. "They were actually kumquats."

Rowena opened up the second one. It was measly lump of half melted gold.

"Really? That's all you could find?" Sam asked disgustedly.

"If you think you can do better, please be my guest," Crowley snapped.

"This will be fine," Rowena said, talking over the both of them. "Now, I need Dean to be present while I cast the spell."

"Cas is working on that," Sam replied, checking his phone again. No messages from anyone. He put his phone back in his pocket and began pacing the length of the warehouse.

"Dean you don't even know if this will work!" Cas protested.

"It's our only hope. You heard what he said about the spell from that book. Cain is willing to do this and so am I. If it works, great. If it doesn't, I take the Mark back and keep fighting the good fight as long as I can," Dean returned.

Cas crossed his arms and narrowed his eyes. He knew Dean was right. But it made him uneasy nonetheless.

"Are you ready Cain?" Dean asked him.

"As I'll ever be, if you two have finished your lover's spat," Cain said. The old man had been standing against the wall. He walked toward the center of the room and held his arm out. Dean grasped his forearm. Cain closed his eyes and grimaced. Red lines streamed out on Dean's skin from the Mark, moving down his arm and back into Cain's. Dean felt a sharp burning pain and cried out as the Mark left his body. He jerked his hand off of Cain's arm, where the Mark once again resided. Cain doubled over, and then straightened up, wincing.

"Do it now Dean!" he cried. "I can't hold on!"

Dean grabbed the First Blade, and stared at the old man in pity.

"NOW!" Cain roared, holding his arm.

Dean lunged forward, his face screwed up, and plunged the First Blade into Cain's chest.

Red light streamed from where the First Blade was stuck in Cain's body. Dean let go of the Blade and dove backwards, pulling Cas down with him. Cain threw out his arms, howling, and red light filled the house.

Then it died down, and Cain dropped to the floor like a stone.

Dean opened his eyes, looking around, his arms still around Cas. He quickly let go, and stood up, looking down at Cain's body. As he watched, the Mark of Cain slowly faded away. Dean quickly pushed up his sleeve to check his arm. Nothing.

Dean exhaled a huge breath that he didn't even realize he had been holding in.

"Cas, it's gone! It's gone, it worked!" Dean pulled Cas up to his feet and embraced him.

"Cas, it worked," he repeated.

"Dean we need to call Sam," Cas said, his voice slightly muffled in Dean's jacket.

Quickly, Dean let Cas go and pulled out his cell phone.

Back in the warehouse, Sam's phone rang. Sam jumped, and then answered it.

"Cas? What's going on?" he exclaimed. "We're waiting!"

"Sammy, it's me. We did it. The Mark's gone," Dean answered.

"What do you mean? Dean, what are you talking about?" Sam demanded.

Crowley and Rowena looked on, confused, while Sam's face turned about three different colors. Finally, he hung up and faced them.

"Dean got the Mark off on his own," he said dazedly.

"What? How?" Rowena demanded.

"Long story short: he didn't kill Cain when we thought he did. He gave Cain the Mark back and then stabbed him with the First Blade. He thinks it worked because he carried the Mark so they were the only ones that could kill each other."

"Are you telling me," Crowley said slowly. "That I went to all that trouble for you to NOT EVEN NEED THE BLOODY INGREDIENTS? Oh how I hate you Winchesters." And with that, Crowley disappeared.

"Always such a dramatic boy," Rowena sighed. "Now, Samuel. Since you have no further need for me, I suggest you let me go immediately." Sam opened his mouth to speak.

"Samuel if you are going to tell me that you will not let me go, I would highly reconsider it. I have no reason to kill you, your brother, or his angel. I have much bigger concerns than you three. And if you do not let me go, you are breaking an oath. And I will get out of here eventually, and I do not take kindly to oath-breakers. So it would be much easier to just let me go," she continued, her accent becoming more prominent as it tended to when she was upset.

"Fine," Sam said. "But first, you're going to make me an oath. You can't think I'm stupid enough to let you just leave. You won't ever harm me, my brother, or Cas."

Rowena smiled and extended her hand.

"I believe we have an accord."

Sam walked to the pole and undid the chains that had bound Rowena. She smiled and stood up.

"Lovely doing business with you, Samuel. I hope to never see you again."

Rowena sauntered to the exit.