Hazzard's compelling narrative follows the life of two beautiful sisters from Australia, Grace and Caro, who seek a new life in post-war England. They face various triumphs and tragedies as they enter into complicated relationships and adventures.

The novel begins with a foreboding sense of threat and uncertainty which remains throughout the novel:

It was simply that the sky, on a shade-less day, suddenly lowered itself like an awning. Purple silence petrified the limbs of trees and stood crops upright in the fields like hair on end. Whatever there was of fresh white paint sprang out from downs or dunes, or lacerated a roadside with a streak of fencing. This occurred shortly after midday on a summer Monday in the south of England.

Hazzard describes how post-war life for all brings a desire for stability, love, and hope, yet many continue to struggle to put their lives together.

She was coming to look on men and women as fellow-survivors: well-dissemblers of their woes, who, with few signals of grief, had contained, assimilated, or put to use their own destruction. Of those who had endured the worst, not all behaved nobly or consistently. but all, involuntarily, became part of some deeper assertion of life.

In reference to the title of the novel, an overarching theme of fleeting, powerful love is compared to the rare occurrence when Venus crosses the sun and appears in a silhouette.

When you realize someone is trying to hurt you, it hurts less.
Unless you love them.

Taking the risk to love and potentially lose one's love is a prominent theme throughout the novel.

Though the dissolution of love created no heroes, the process itself required some heroism. There was the risk that endurance might appear enough of an achievement. That risk had come up before.

The sisters experience love and marriage but also betrayal and heartache.

But, with unintelligible nostalgia for a life she had never lived, knew that all would have been subtly and profoundly different had her husband greatly loved her.

Caro loves Paul, an indifferent and handsome man who does not treat her well. Caro faces heartache, as Paul later marries another woman.

Paul said, 'You always had some contempt for me.'
'Yes.'
'And love too.'
'Yes.' A flicker over her stare was the facial equivalent of a shrug. 'Now you have a wife to give you both.'

Caro, too, moves on to marry another man—a wealthy American.

'That alas is the way it goes; Something we must rectify.' Paul, not Caro, would interpret the degree of meaning in their respective lots. That had been decided, as he sat speaking intimately of his life to the person most excluded from it - in order to readmit her to the intimacy, though not the life.

Shirley Hazzard’s The Transit of Venus follows two sisters, Caro and Grace, throughout several decades of their lives. After they are orphaned when their parents are killed in a ferry accident, they are raised by their half-sister, Dora. They grow up quite a bit once orphaned.

Even children—children who had not yet experienced virtue and might be ruthless in tormenting playfellows—were struck adult in pity: the Great War being deeply known to them, learned before memory, as infants know the macabre from dreams.

They emigrate to England from Australia. Grace marries immediately, but Caro falls in love with Paul Ivory; he is a man who doesn’t treat her well and eventually marries another woman, Tertia. Caro and Paul do carry on their affair after Paul becomes involved with Tertia, but when she becomes pregnant, he...