The heart.
Four chambers. Two sounds. One of the most intriguing organs of the human body. Simple, yet profoundly intricate. A design essential for life wrapped within complexities still not fully understood.
True, many other creatures have hearts. Of course, these work more or less in the same manner as every other. But the human heart is different. It's special. The capabilities of strength simultaneously intertwined with the potential for weakness sets it apart as unique. Because it is, at its center, a conduit for who we are on the inside. It's where loyalty and attachment reside. Where the seat of emotion and desire can be found. And possibly the greatest emotion one can feel is that strange tingling sensation at the base of one's chest after seeing the One. That one person whose life completes that of our own.
Everyone has felt it at one point or another. For most people, though, it's a rarity. As everyone knows, the ability to truly discern the difference between truth or trickery within the heart is almost impossible.
For Rory Williams, however, it was only a matter of truth.
Amy Pond was the only woman he wanted to spend the rest of his life with. She was his only love.
His companion for all time.
And every time they ran, his heart pumped a little bit faster. Each time they held each other, the feeling shook his chest. And when she told him how she really felt, or when she called him an idiot like she always did, it was those two sounds. The beat of his heart. Yes, it was those simple, yet complex noises that resonated louder than any other sound in the Universe. It was these sounds that reminded him that there is no obstacle too big, no monster too ferocious, no circumstance too improbable that could stop him from loving her.
Even if he should die, it was his heart that was proof.
His heart. And the simple sounds it made.