Love and happiness - hatred and despair... Life seems to alternate between periods of stunning happiness for pretty seventeen-year-old Sheryl Williams after she marries dashing soldier Alun Powell, and times when bad luck and despair almost drown her happiness forever. When their baby Caitlin is born and Alun, having recently left the army, is unable to find work, they are reduced to living in the slums of Cardiff's Tiger Bay. Their life together is full of rows and recriminations and when Alun is involved in a vicious fight and imprisoned, estranged from her own family a desperate Sheryl is forced to turn to the Powells. At first reluctant to help, they agree to take in little Caitlin whilst Sheryl seeks work in Cardiff. But Sheryl soon spirals into a life of unhappiness and despair. Until one fateful day, seven-year-old Caitlin takes off for Cardiff in search of her mother. As night falls and the police continue to look for the young girl, Sheryl fears she will never see her beloved daughter again ...