Laird's son and poor man's daughter.
The Laird's son was courting the daugher of an old man on the estate. Her father was in danger of being evicted because of this, so his daughter left to protect him and found a passage overseas on a ship in exchange for cooking and cleaning.
She found a job in a big house when the boat docked. The man of the house forbid her to enter one room, but she went in when he was away. She found seven dead women inside, and the white key which opened the door turned black. She fled to find the boat which brought her and the crew hid her when her master came in search of her.
She went home and the Laird's son wanted to marry her. She told him he must get his own place, even though he had no money. There was a place for sale nearby and, just as he put in a successful bid, a rider approached, asking if the place had been sold and to whom. He gave the boy a purse containing more than enough to pay for it. The couple married.