Amber Black and The Sorcerers Stone

When Arthur Weasley found a baby on top of a trunk in the ministry you could say he was surprised. Attached to the baby was a note with only a name: Amber Black.

9 years later Amber heads to Hogwarts on a train with her brother Ron Weasley where they meet the famous Harry Potter who sweeps them into a mystery and a possible conspiracy against Hogwarts