A South Wales mining town, 1947. Tom Thomas is torn between his commitment to improving conditions in the newly nationalised mine, his own prospects, and his passion for Olwen, which he knows to be reciprocated.

Olwen, the daughter of miner Ted Williams and his wife, wins a music scholarship to University College Cardiff and is determined to put the restricting poverty of her upbringing behind her. Alfred Collins, an English industrial psychologist, steps in to offer married life and singing opportunities in London, which Olwen accepts, making clear her rationale to Tom. However, she finds that the London streets are not paved with gold and that she is far from home.

Emrys, having had the satisfaction of seeing for himself how unhappy Olwen is with her 'diamante' lifestyle in London, returns to the devoted arms of a true but rather insipid diamond - physiotherapist Glenis. Glenis is a friend of Olwen's who has managed to carve out a career for herself locally and who tended Tom during his stay at Talygarn, a rehabilitation home for miners, after an accident at work. Home is where the heart is, as Olwen learns to her cost, and it is where Olwen's brother Thomas and her grandmother are seen to great effect in the family scenes. Home is also where Ted dies, unusually alone, of 'dust on the lung' while listening to a boxing match on the radio.