William Ashton, retained as a gardener by Edward Hillier, discovers his new master to be a detached and driven man. Over the years, as travail and tragedy bring them closer together, he understands that they have more in common than he first realised, but the affection they feel for one another will be sorely tested by boundaries both of class and of rigid Victorian morality. Like the private garden behind the high walls their love must flourish only in the strictest secrecy – or else it will not do so at all.