Ground wire on Jeep burning?

[demon]

I have an 84 Jeep Wagoneer and it was running fine and all of a sudden it just died at a stop sign. It would not even turn over after that. When i turn the key to the acc position, it lit up the clock and the radio face. I messed with all the wiring under the hood and all of a sudden the light came on under the hood. I tried the key and it started. Then, it started bellowing smoke from under the hood near the battery, I opened the hood and the small ground wire from the battery to the body (fender) was smoking and all the plastic was melted off. It was so hot that it started on fire. Please tell me what would be some causes for this so I can check it out. Thanks in advance!! Dan