"The awesome castle towered over treacherous sea cliffs-- and the household there held whispers of another kind of treachery. Caroline's marriage to Lady Malvina's son would open up to her a world of wealth, power and aristocracy, but an overpoweringly handsome man, the heir of Castle Heritage, tried to block her way. He offered her a kind of love she had never known exited. But Caroline had no time to think, for an unseen hand seemed to rush her into matrimony, the same hand that had trapped the castle in a giant web of intrigue. Death were certain for those who tried to escape." Back cover copy and I also find it confusing, especially the last sentence!
Used availability for Elisabeth Barr's Castle Heritage
January 1978 : USA Hardback
May 1977 : UK Hardback
January 1980 : USA Mass Market Paperback
January 1979 : USA Mass Market Paperback