Many people think there's nothing they can do to change their karma - it's preordained so why bother trying to change their situation? This is what scares people. These folks think that to accept the reality of karma one must be passive. It simply isn't true. Karma is active. We can - in the blink of an eye - make decisions that will shape our futures and transform the parts of our lives that are causing us unhappiness.
Karma is the universal law of cause and effect. You reap what you sow. You get what you earn... If you give love, you get love. Revenge returns itself upon the avenger. What goes around comes around... Karma is justice. It does not reward or punish. It shows no favoritism because we have to earn all that we receive. Karma doesn't predestine anyone or anything. We create our own causes, and karma adjusts the effects with perfect balance.
Death is birth into the realm of the spirit.