Mary was a human. She was a bright eyed 71-year old woman and married to Bill.
In May 1927 Mary and Bill both lived together in a house in Hampshire, three miles away from the next village. One night, two Groog knocked on their door.
A short time later Rory Williams arrived at the house. He had lost Amy Pond and the Eleventh Doctor. Then it seemed that they were all attacked by an enemy that they could not see. Together Rory, Bill, Mary and the Groog tried to fight the enemies.
However, the enemies were Amy and the Doctor, who were trapped in an other dimension and tried to contact Rory, Bill and Mary. Amy and the Doctor thought the Groog were the enemies and tried to help Rory and the others.
After Amy and the Doctor returned from their dimension, Bill and Mary invited Amy, Rory, the Doctor, Lan and his friend to breakfast and everyone accepted the invitation. Mary was happy and told the Doctor that it had been such a long time since they had a full house. (AUDIO: The Empty House)