Huw is the youngest son of the large Morgan family, growing up in a close-knit Welsh mining valley. After an accident in the snow leaves him confined to a bed for five years, he spends his time observing his family and reading voraciously. This period of quiet observation and academic development sets him apart from his brothers, leading him toward an education rather than an immediate life in the coal mines. He is deeply devoted to his family and struggles to understand the changing political and social dynamics of his town.

Gwilym is the patriarch of the Morgan family and a respected leader among the local miners. He serves as a deacon in the chapel and maintains a strict but loving Christian household. While he believes in fair wages for honest work, he favors traditional, non-confrontational methods of resolving disputes, putting him at odds with the radical union politics adopted by his older sons. He prioritizes his family's unity and moral standing above all else.

Beth is the hardworking, fiercely protective matriarch of the Morgan family. She dedicates her life to her children and her husband, taking particular pride in keeping a clean, well-fed household. She dislikes the radical union meetings, viewing them as a threat to her husband's safety and her family's stability. Her protective instincts drive her to confront groups of striking men when she feels her family is threatened.

Bronwen marries into the Morgan family and quickly becomes an essential, beloved presence in their lives. She lives nearby and spends significant time in the main house, offering warmth and practical support. When Huw is injured, she takes on the role of his primary nurse, establishing a deep, lifelong bond with him. She represents emotional intelligence and refuses to be bound by community gossip.

Reverend Gruffydd is the educated, principled leader of the local chapel. Despite his intellectual background, he is extremely poor and relies on the community for his daily needs. He supports the miners during their strikes and attempts to guide the congregation through periods of starvation and moral panic. He practices strict self-denial, especially regarding matters of the heart.

Angharad is a spirited daughter of the Morgan family who often feels trapped by the expectations placed upon women in the Valley. She holds deep affection for Reverend Gruffydd but finds herself courted by the wealthy Iestyn Evans. Her choices reflect the difficult balance between pursuing personal happiness and securing financial stability for herself and her family.

Ivor is the eldest of the Morgan sons. He works in the mines and remains staunchly loyal to his father's traditional views, choosing not to join his younger brothers in their early union protests. He is musically gifted and leads a local choir that achieves significant renown, representing the cultural pride of the Welsh mining community.

Davy is the most academically inclined of the older Morgan brothers, originally hoping to become a doctor before economic realities force him into the mines. Frustrated by the exploitation of the workers, he becomes a prominent leader in organizing the miners' union. He is willing to fracture his family temporarily to stand up for socialist ideals and fair working conditions.

Owen is a quiet, industrious engineer among the Morgan brothers. Instead of focusing solely on the union like Davy, Owen spends his time working on an engine designed to cut coal more efficiently. He experiences early romantic heartbreak which drives him to focus even more intensely on his mechanical inventions.

Ianto is the second eldest Morgan brother. He spends significant time away from the Valley, traveling to London and facing personal tragedy before returning home. He brings an outside perspective to the village and channels his grief into fiercely protecting his sisters and lobbying the government for better mining pay.

Gwilym Jr. tends to agree with his brother Davy regarding the necessity of standing up to the English mine managers. He follows the strike leaders out of the family home and later establishes his own household in a neighboring valley. He travels to America with his brother Owen to promote new mining technology.

Ceridwen is one of the older Morgan sisters. She participates in the bustling domestic life of the household and eventually marries Blethyn Llywarch in a double ceremony alongside her sister Angharad. She represents the traditional path of courtship and marriage in the Valley.

Marged is a local woman whose presence creates a romantic rivalry within the Morgan family. She initially falls in love with Owen, but interference from their families causes the relationship to dissolve. She eventually marries Gwilym Jr., though she continues to struggle with emotional stability and unresolved feelings.

Iestyn is the wealthy son of the local English mine owner. He courts Angharad Morgan, bringing London society habits and financial security to the relationship. His presence causes tension among the working-class Morgan brothers, who view him as representative of the management they are striking against.

Dai Bando is a rugged, skilled local boxer who takes on the task of teaching young Huw how to defend himself. He embodies the physical toughness of the Welsh valleys and fiercely protects the people he cares about. When Huw is abused by a teacher, Dai exacts brutal revenge on the man.

Cynfartha is Dai Bando's constant companion and friend. He works in the mines by day and helps run the pub they purchase together by night. He provides steady support to Dai and participates in defending the mines and the community during the violent strikes.

Ceinwen is a forward, confident schoolgirl who actively pursues a romantic relationship with Huw. Unlike the reserved women in Huw's family, Ceinwen states exactly what she wants, demanding gifts like nightingale eggs and boldly kissing him. She represents a simpler, more direct alternative to Huw's complicated feelings for his sister-in-law.

Mr. Jonas is a teacher at the National School who deeply resents his own Welsh heritage. He actively punishes students for speaking Welsh and acting in ways he perceives as provincial. He targets Huw with physical abuse, acting as an agent of English cultural domination in the classroom.

Elias is a local shopkeeper with a bitter disposition who frequently clashes with the Morgan family. He attempts to steal the Morgans' prized white turkeys to punish Gwilym for what he perceives as pride. He holds grudges and uses his resources to hire lawyers against the family when opportunities arise.

Olwen is the youngest daughter of the Morgan family. As she grows up, she witnesses the increasing violence of the miners' strikes and attempts to care for the vulnerable pit horses during the riots.