When Harrison Tolly learns that he is the rightful heir of Ashwood and may petition to be its Earl, he has a huge dilemma to face and harbours a dark secret. The young woman he is married to is not really his wife, but the sister of Lady Carew, who had been impregnated by her sister's husband, Lord Carew. Harrison Tolly has agreed to pretend she is his wife because he is secretly in love with Lady Carew. The sort of scrutiny that would follow the discovery that he is now suddenly an earl would ruin the countess.

Olivia Jameson, Lady Carew, is unaware of Harrison's devotion to her. She does not know that he is the one who has begun to secretly woo her with small, discreet gifts and messages. She does not know that when she writes letters to this Scarlet Pimpernel, (and signs them Lady X), that she is falling in love with him. When her husband is killed in a senseless accident, her scarlet pimpernel becomes bolder, coming to her room in the middle of the night.