1964, Apartheid South Africa. Danie du Plessis, the son of a conservative Afrikaner family, is poised to start a glittering legal academic career at one of South Africa's leading universities, when he falls in love with a student, Amy Coetzee. But there's a problem: he's white, she's not. Facing arrest, imprisonment and ruin, the couple flee South Africa, and settle in Cambridge, where friends find them positions at the University. They marry and have two children, and have seemingly put the past, and South Africa, behind them. But in 1968 Art Pienaar enters their lives, and, insisting that they have a duty to fight back, enlists their help in increasingly dangerous schemes to undermine the South African regime.