Vesuvius - this was the mission on which the success of D-Day depended. The chosen squadron was no. 633, and their target was a fjord in Norway, where the Germans were known to be developing something so secret that not even the crews of the Mosquitoes which were to fly on the mission could be told about it. All they do know is that they will be flying in low, between the steep mountain walls, without fighter support. Most of them will be flying one way only...