Blue Heather by barbara cartland

Brigadier Ian McCraggan, who had headed many secret and diplomatic missions abroad, discovers he has inherited Skaig Castle, in the highlands of Scotland. Exhausted from his work and eager to return to his beloved castle, he travels to Edinburgh with his fiancée, the society beaty Lynette Trent and his wealthy American mother. 

From there he goes alone to the castle to find it not only in a state of disrepair but also occupied by squatters. Seeking advice from his inarticulate cousin, the Duke of Arkrae, Ian soon finds that the Duke has problems of his own — his precious pot of blue heather, that he has be secretly cultivating, has been stolen.

As they begin a mission to discover the whereabouts of the blue heather, Ian also finds mysterious forces are challenging his inheritance and his very happiness. What will he find at the end of the trail? And, as different worlds collide, how many difficult and comic situations will he undergo before the heather is found?