Boyo lives with his brother Sid, his sister Gwenny and their elderly mother Marlene in an economically depressed area of South-West Wales. Their father has vanished when they were small children, apparently headed for America. The leather-jacketed, motorbike-riding Sid has grown up obsessed with American culture and dreams of joining his father in the States. When the brothers discover that an open-cast mine is opening nearby they join the scramble for jobs, but their mother is unaccountably against the idea. On the morning when they need to report for work, they find she has sabotaged Sid's bike, scuppering their chances of employment. Sid and Gwenny begin to spend more and more of their considerable spare time together, washing down medication they've obtained under their mother's name with pilfered booze. Marlene's increasingly eccentric behaviour leads to her being interred in a hospital, but Boyo is powerless to stop his brother and sister from drifting dangerously out of touch ...