SES Light need help

[NegativeZero]

first off, hello. I'm currently getting a SES light. So I hooked up the code reader and received the following code:

P0420

I looked it up in my hanes manual and they refered to it as a "catalyst system efficiency below threshold (bank 1)"

Any idea on how to fix this, has anyone else gotten this code? Any help woulp be appreciated. Thanks.

[98Camaro3.8]

Bad cat. Do you have a high flow cat, or the stock one? If you've got a stock cat, you're gonna need a new one. If it's a high flow cat, you'd be fine with an O2 simulator.

Edit: I see you're in California. You best bet is to just get your cat replaced with another stock one.

[NegativeZero]

to my knowledge, i think it still has the original cat. so its the cat that has to be replaced?