"A diamond plate, a glowing grate, a place you never leave. where am I?"

This is a story set in the future, where aliens rule the Earth and kidnap kids to "experiment" on them by giving them super human abilities. They can't choose which abilities they get, sometimes they might get two or maybe three, it's most common though to just get one. The aliens look like Human's, but that's just a disguise, they can steal someone's looks by sucking their souls out.