I got this idea for a story while watching a TV show about heart transplants and the phenominon of people taking on the personality traits of the person's who's heart they received, and I came up with an idea for a story.
Characters involved: Boy who is killed in an accident, boy's family, girl who receives his heart, her family (I'll let you name them)
Mood of plot bunny: Sad, mysteroius, discovery
Plot line: The story starts with the girl in the hospital getting ready for surgery, and her parents being told about the heart she will be receiving, then shifting to the wizarding family, who is being told their son, who ran away, has been killed.
In the next chapters, the girl who receives the heart start being able to perform limited amounts of magic, starting to wonder if her new heart might have something to do with it, so she tries to find out where her heart came from.
It should also include the girl finding the boys family, but I'll let you come up with your own ending.
Other details:You'll need to work out the details of just how receiving a wizards heart would give a person limited magical powers, but it will give you a chance to be creative.