As the billionth customers at a space tollport the Doctor and Mel win the Grand Prize – a place on the Fabulous Fifties Coach Tour to Disneyland, Planet Earth. Unfortunately, they don't quite make it there ... Knocked off-course by a wayward satellite the coach party arrives instead at Shangri-la, a remote Welsh holiday camp. But the peace and quiet of the countryside are soon shattered by the arrival of an army of marauding Bannermen soldiers, led by the ruthless Gavrok. They are tracking down Delta, the last of the Chimeron, with only one thought in mind – her destruction...