2007 Peugeot 307 car won't move forward

I was driving at around 110 kmph (68 mph) up a hill when suddenly there was a spike in the revs. Then the car appeared to go into limp mode. Whenever I prodded the accelerator, it felt as though it was "slip revving". I then coasted to a stop in a safe place and stopped. I did a brief check on the car to see any obvious problems, didn't see anything. Then re started the car and tried to pull off, but then the car refused to move forward (or back) at all. The engine revs fine, but car does not move at all.