"What? Why?" asked Sherlock, he was very annoyed, because he knows Amy would do it. It was very predictable of her.
"I-" she paused. "-don"t fully know. But I feel like I really need to be there." She looked down in sorrow.
The Doctor finally spoke: "It's a fixed point in time. I can sense it. I could sense them miles away."
Amy and Sherlock looked at the Doctor. Amy"s face described disbelief and confusion, Sherlock looked at the Doctor angrily.

"Amy is not going to war to fight with those creatures!" he started arguing with the Doctor.

"It"s a fixed point! It has to be done or your future won"t be the same any more! Why people always ignore my warnings?" he sighed before continuing again. "Think about it. When Amy doesn't fight in this battle and bring them to victory, you and Amy might not be born again."

"But Doctor, this wasn't supposed to happen." Amy added her voice into the conversation. The Final battle was supposed to be Castillon, no?"

"No, Amy, humans tampered with the written version of History. This is the final battle, this is where you fight and end it all. I can't tell you why, but this is it."

"No, I can"t allow this!" Sherlock showed his arrogance and care for Amy. "What are the chances that she will die in battle?"

The Doctor stayed silent and looked at Sherlock with a sorrowful expression on his face. Sherlock"s fury got stronger, but he didn't show it in front of Amy.

"Thought so," he said and walked out the cell. "I'm fighting beside her. End of discussion."

Amy didn't know what to feel. Maybe coming adventuring with the Doctor wasn't the brightest idea and she can sense anger aura surrounding Sherlock. He isn't the strongest marble in the bag, but he is very clever when it comes to paralysing limbs. Her love for him is still strong and her heart tells her to go talk to him. She looked at the Doctor and he nodded in agreement. Amy smiled at him and ran after Sherlock.

"Sherlock! Wait!" she called out to him and it turns out he had already found a way out of this place, though it felt a bit of a maze for Amy.

Sherlock turned around. "Yes," he said. "what is it?" He looked the same as before they came here. He must have deleted, what had happened, from his brain. He usually deletes information, what he thinks he doesn't need and that small argument really wasn't what you should keep in your mind for long.

"You"re right. We should fight together. We promised each-other the day we discovered how much we trusted each other." she smiled. "Remember that?"

Sherlock"s frown turned into a slight satisfied smile. "Yes, I do." he answered. "it"s stored to the safest part of my mind, where limitation is completely banned."

Amy walked up to him and caressed both his hands. "So, promise me, that we will fight to the end, together. Me and you. JUST me and you. We"ll stick together and looked at each others backs and survive together."

"And if the events turn against us, we will die in each others hands." Sherlock added. "When I depart from this time or world, it's your face I want to see before I die." he took one of his hands and caressed Amy's blushing cheek with it. "And I want you to be the last person I touch."

"Promise?" Amy asked with tears of joys in the corner of her eyes.

"I promise."