In an alternative 1980s London, Charlie, drifting through life and dodging full-time employment, is in love with Miranda, a bright student who lives with a terrible secret. When Charlie comes into money, he buys Adam, one of the first batch of synthetic humans. With Miranda's assistance, he co-designs Adam's personality. This near-perfect human is beautiful, strong and clever - and soon a love triangle forms, which leads Charlie, Miranda and Adam to a profound moral dilemma. What makes us human? Our outward deeds or our inner lives? Could a machine truly understand the human heart?