Hanna and Simon are in a long-term relationship which, though loving, has grown sexually unexciting. Soon after Simon's mother dies from advanced pancreatic cancer, he discovers that he has testicular cancer and must undergo surgery and chemotherapy. The night of his surgery, Hanna has a sexual encounter with a man called Adam, and Simon learns that he had fathered a child seventeen years earlier, although the woman opted for an abortion. Simon, who had assumed that either he or Hanna was infertile, is assured that he should still be able to have children after his surgery. During his recovery, Simon and Hanna decide to finally wed. Shortly beforehand, Simon encounters Adam at the pool and begins an affair with him as well.