- For the character's history in Supernatural, see Mary Winchester
|Dates||December 5, 1954|
|Episode(s)|| 1.01 Pilot (The Winchesters)|
1.02 Teach Your Children Well
1.03 You're Lost Little Girl
1.04 Masters of War
Mary Campbell is the daughter of Deanna and Samuel Campbell. Mary was raised to be a hunter by her parents from a young age. She was very close to her cousin Maggie, who was killed in 1971 by a vampire. Following Maggie's death, Mary has decided to leave hunting, a fact she argued with her father about before he suddenly disappeared while on a hunt. At the time of his disappearance, her parents were separated, having had relationship difficulties since Maggie's death. She had previously stayed with hunter Tracy Gellar in Kalamazoo when her parents were having marriage issues.
Mary's father Samuel has gone missing while on a hunt. In her last conversation with him, he sounded afraid, and told her she needed to retrieve a file from an address in Lawrence; information he'd obtained from Ada Monroe. At the location she finds John Winchester, who has been directed to the same address by a letter from his father, handed to him by a mysterious man.
John has a key that opens the magically warded door, which leads to a clubhouse for a group called the Men of Letters. Mary finds the schematic that her father, was after, while John finds items belong to his father who was apparently a member of the secret society.
With help from her friends Carlos and Latika Dar, they follow Samuel's trail to New Orleans, and in a tomb guarded by a Loup-Garou retrieve a box that can trap and kill monsters.
Ada tells them Samuel Campbell was looking for a way to defeat a supernatural being called the Akrida which is trying to invade Earth.
Following Samuel's trail, Mary , John, Latoka and Carlos investigate disappearances at a commune. Mary and Carlos clash as he confronts her about her autocratic leadership style. Ignoring advice from Latika puts John in danger from the monster they are hunting - La Tunda - although they eventually rescue him and kill the creature. Mary acknowledges she needs to change her ways and work as part of the team.
Mary is still fixated on trying to find her dad. Kids who live next door to Mary are kidnapped and while investigating, she confesses to John that she has no idea of who she is or what she wants outside hunting. She enters the monster's lair to rescue the children, and must let go of some of that fear in order to escape. After the hunt, Mary goes to the movies to see The Omega Man with a guy - Kyle - she meets by chance at the box office.
Mary is still dealing with her grief and guilt over Maggie's death, and can't even bear to enter her bedroom. While she and the team investigates the suspicious deaths at a veteran's hospital, she finds out that Kyle, is an investigative report who's been looking into the deaths of veterans in psych wards across the country. After the hunt, Mary agrees to let Carlos stay in Maggie's old room.