What damage could have happened to my car if an incorrectly connected stereo

[lando83002]

burned up and started smoking? I have a 1998 Honda civic and I just tried to replace the aftermarket Kenwood stereo with an Alpine stereo. I unplugged the wire connector from the Kenwood and noticed it was the same type of connector as the Alpine so just plugged it into the Alpine. I turned the car on and the Alpine immediately started smoking. I removed the Alpine and put the old stereo back in, but it doesn't work anymore. I checked the radio fuse in the car and it is fine and the wires don't look burned or melted. I know the Alpine is probably destroyed, but I'm baffled on what damage could have happened to the car wiring. Any ideas why the old stereo isn't working now?