When an English cartographer arrives in Wales to tell the residents of the Welsh village of Ffynnon Garw that their “mountain” is only a hill, the offended community sets out to remedy the situation. The film is based on a story heard by Christopher Monger from his grandfather about the real village of Taff’s Well, in the old county of Glamorgan, and its neighbouring Garth Hill. However, due to 20th century urbanisation of the area, it was filmed in the more rural Llanrhaeadr-ym-Mochnant and Llansilin areas in Powys.