The moment the heart stops, the body begins to change, and it does not wait. Within minutes it pales and starts to cool. Within hours it stiffens. Over days, the body's own bacteria and enzymes break it down. None of this is gruesome to the person, who is beyond feeling anything. It frightens the living, so here it is in plain language.
This page is the after. For the process leading up to it, read what dying actually looks like. For what people mean by the soul or an afterlife, read what happens after you die.