Set in 1917, the film follows two English cartographers, Garrad and Anson who go to the fictional Welsh village of Ffynnon Garw for measuring its mountain, but finally they come to conclusion that it is only a hill because of its under- required-1000 feet height. The villagers make a plan to delay the departure of the cartographers while they attempt to build an earth cairn on the top of the hill to make it high enough to be considered a mountain.