In 1960s Czechoslovakia, Tomas, an oversexed Prague surgeon, marries Tereza, a beautiful, waiflike country girl. Even though he has taken a vow of fidelity, Tomas continues his wanton womanizing, notably with his mistress Sabina. Escaping the 1968 Russian invasion of Prague by heading for Geneva, Switzerland, Sabina takes up with another man and unexpectedly develops an unlikely yet stimulating friendship with fellow refugee Tereza.