The Immortals Prison Hearts

There was always something whispering to him, ever since he could remember he could hear it in the back of his mind, just itching for release, but he never listened. Never let it out. Years after his parents dissapeared, Peter had completely shut down, he had very few friends, no one on his side, and it was how OtheyO wanted it and it was how it stayed... At least till OsheO turned up. Just what is it locked down inside our hearts?