It's 1905 and in Pontypridd coal is king. The families who sank the first collieries are rich, though no one is wealthier than Harry Watkin Jones. At twenty, his daughter Sali is about to marry businessman Mansel in Pontypridd's wedding of the year, but when tragedy strikes Sali becomes a penniless outcast, struggling to support herself and her son in a world very different to the one she once knew. When she becomes housekeeper to a family of colliers, Sali finds herself denying her roots and sacrificing her son's future to be with the people she has come to love.