The sundial.

When the Halloran clan gathers at the family home for a funeral, no one is surprised when the somewhat peculiar Aunt Fanny wanders off into the secret garden. But then she returns to report an astonishing vision of an apocalypse from which only the Hallorans and their hangers-on will be spared, and the family finds itself engulfed in growing madness, fear, and violence as they prepare for a terrible new world.