In a castle in Yorkshire a baronet with a dark secret has become obsessed with the idea of leaving his castle in a state of perfection for his handsome heir. From London comes an ambitious architect with grandiose ideas, and Olivia, his beautiful and impulsive daughter. In this tale of passion, mystery and tragedy set at the time of the Seven Years' War (1756-63) these prove an explosive mixture. When her father and the baronet fall out is Olivia to be thwarted in love as well as in her hopes of ever unravelling the castle's secret? Is young Gerard Kirby worthy of her love and in the end who truly is the heir to Castle Kirby?