Hoping to find work in Wales, David Goliath (Paul Robinson), a ship's stoker, boards a train and winds up in a small mining town. There, his powerful physique and magnificent singing voice attract the attention of Parry (Simon Lack), the choir director, who hopes to win the national singing meet on the strength of David's vocal chords. Goliath soon finds himself embracing village life, working down the pit and singing with the choir. However, when a cave-in leads to disaster, the mine is closed and all the workers are left unemployed. Hoping to convince the owners to reopen the colliery, Goliath helps lead a group of activists in a walk to London. Along the way, they learn war has been declared, and begin to plan to get the mine up and running again in time to server the nation's needs.