Mick and Leda Daniels' identical twin boys, Alex and Phillip, grow up on Trafalgar Downs Station in the Goldfields-Esperance region of Western Australia. Their older, musically gifted 'sunshine sister', Helen, brings joy to everyone with her talents. Leda Daniels looks after the twins' early childhood education, then teaches them in classroom situations when she makes an unplanned return to teaching at Leonora District High School. Mick makes sure the boys are well-coached in sporting pursuits and that they learn hard lessons about the responsibilities associated with working on a cattle station.

Sent to the historic and traditional Blackwood Boys' Boarding College in the metropolitan area for the last three years of secondary school, both Nick Floyd and Myles Bennett have significant impacts on their lives. The twins have to deal with a family crisis, and they take different pathways but always remain 'two halves of the one person'.

Their exceptional swimming talents see both twins selected to represent Australia at the Olympic Games in Mexico City in 1968. In 1970 they are required to register for National Service and face the dreaded 'ballot of death'.

Later, Phillip assumes the responsibility for helping to run Trafalgar Downs Station while Alex studies archaeology and anthropology at university. Jonathan Budd enters Helen's and the twins' lives. The unique connection between identical twins is severely tested by subsequent events.

This is all part of the story of the Trafalgar Downs' twins.