Every night in the small harbor town of Sealey Head, just as the sun goes down, an invisible bell tolls. It's happened every day for as long as any of the inhabitants can remember, and most of the inhabitants don't even notice it anymore. But a few of the younger people are fascinated, or perhaps even obsessed with it-- Judd Cauley, the innkeeper's son; the merchant's daughter, Gwyneth Blair, who sits at her little desk in the attic and writes story after story trying to make sense of the bell; and even a visiting scholar from the city, Mr. Ridley Dow. Emma, who works as a scullery maid at Aislinn House, also knows there is something magical about the place-- ever since she was a child, sometimes the doors in the house open onto a castle in some other place, where she sees a girl near her own age, a princess named Ysabo.
