When a Scot Ties the Knot (Castles Ever After #3) by Tessa Dare

In order to avoid social situations, Madeline Gracechurch tells a small little lie - she is engaged to Captain MacKenzie. Everyone believes him to be real, but Maddie has completely made him up and sends him fake letters to prove her devotion. After many years of this deception, she fakes his death and everyone leaves her to live her own life. After she's inherited a castle however, the real Captain Logan MacKenzie shows up, ready to get married like she promised in her letters.

Say Yes to the Marquess (Castles Ever After #2) by Tessa Dare

After an eight year engagement to Piers Brandon, the Marquess of Granville, Clio wants out. She has recently inherited a castle and has big plans for her future. The only problem is that the Marquess has been out of the country for months and has no expected return date. Champion fighter Rafe needs his brother, the Marquess, to get married, so he takes control of planning the wedding while his brother is abroad.

Romancing the Duke (Castles Ever After #1) by Tessa Dare

After being left a castle in her godfather's will, Izzy spends the last of her money to travel to what turns out to be a run down and already owned castle. Ransom, the Duke of Rothbury, has been living in the castle since an incident that left him blind. Izzy has nowhere else to go, so she and the Duke must learn to live in the same castle.