Set in the 80s and Diana is working at the Smithsonian with Barbara Minerva. One day Minerva is working with a strange rock and it turns out it's a wish stone. Diana doesn't believe it but she wishes for Steve to come back to life, and he does but it's like Quantum Leap. He inhabits the body of another guy, but Diana sees him as Steve Trevor. Maxwell Lord is like an 80s Donald Trump oil baron, but he's secretly broke. He takes the wish stone and wishes to become the stone itself. So he's able to grant wishes by touching someone (of course he becomes rich), but the stone is the Monkey Paw. For each wish it takes something away. So when Diana wished Steve back to life, she lost her powers (thus the golden armor she wears).
So what Max loses is his health, so he needs more people to wish to give him health and keep him alive. So his big plan is to use a satellite system to have people make wishes to him through their TVs from all around the world.
Cheetah? First Barbara wishes to be like Diana "strong and sexy". They have a fight, and then Barbara wishes to be "an apex predator" which is what turns her into Cheetah.