The Key to Her Heart by Blanche Dabney

The key to her heart is waiting in medieval Scotland.
Delivered to the past… When Daisy Stone delivers a parcel to a crumbling highland castle, she’s not looking for love. But when a silver key unlocks a door to the past, she steps through and finds the man of her dreams waiting on the other side.

A gift from the future… Laird Jock MacGregor has fallen for a beguiling woman no one can find. One minute she was right there in front of him, the next she was gone. The sole clue to finding her again is sitting in the palm of his hand. If only he can work out what it means.

The key to it all… Ever since Daisy returned home she’s tried to forget the brawny medieval highlander who stole her heart. She’s certain she will never see him again. Until she gets a knock on her door.